JPH11184822A - Graph display device/method and record medium where graph display processing program is recorded - Google Patents

Abstract

PROBLEM TO BE SOLVED: To sequentially display a corresponding figure and graph while variable values of plural variables contained in a formula for segment plotting on a coordinate are separately changed to arbitrary values in a graph display device for plotting and displaying the figure and the graph, which correspond to inputted graphic plotting data and function formula data. SOLUTION: The two variable (s) and (t) contained in an arbitrary coordinate change formula of respective apex coordinates A, B and C for dynamically displaying figure data are separately changed to the arbitrary values with the operation of '↑' '↓' or '←' '→' cursor keys 12g-12j in variable value display bars B1 and B2, and they are changed into figure data corresponding to the coordinate change formula for which the corresponding variable values are substituted so as to dynamically display them.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a graph display apparatus, a graph display method, and a program for recording a graph display processing program for drawing and displaying a graphic or a graph corresponding to input graphic drawing data or function formula data. Regarding the medium.

[0002]

2. Description of the Related Art Conventionally, for example, in an electronic calculation device having a function calculation function, a device which inputs a function expression and instructs to draw a graph, draws and displays a graph corresponding to the input function expression is practical. Has been

That is, for example, when a function formula of Y = X ² is input, Y values corresponding to respective X values in a preset X coordinate range are calculated and displayed as a graph.

In such a conventional graph display device, for example, a variable A is specified in an input function expression (Y = AX ++ B), and a value to be substituted for the variable A is set in an arbitrary range.
There has been proposed a system having a graph display function called a dynamic graph in which graphs corresponding to the respective functional expressions when changing at an arbitrary interval are sequentially drawn and displayed. According to this, it is possible to easily grasp how each graph changes when one designated variable of a certain function expression is changed.

[0005]

However, in the dynamic graph function of the conventional graph display device, one variable included in a function expression is designated, and the function corresponds to each function expression when its value is sequentially changed. Although it is possible to easily understand the change in the entire graph, it is possible to sequentially display the corresponding graphs while changing each variable value of the two variables included in the function expression to an arbitrary value separately. Can not.

For this reason, there is a problem that it is not easy to analyze a complicated graph or a graphic (three-dimensional graph) in which a plurality of coordinate points change together. The present invention has been made in view of the above-described problem, and sequentially corresponds to each of the plurality of variables included in the equation for drawing a line segment on a coordinate while changing the variable values to arbitrary values. An object of the present invention is to provide a graph display device, a graph display method, and a recording medium on which a graph display processing program is recorded, which can display figures and graphs.

[0007]

That is, a graph display device according to claim 1 of the present invention comprises: expression input means for inputting expression data including a plurality of variables for drawing a graph;
Variable value display means for displaying the value of each of a plurality of variables included in the expression data input by the expression input means,
A variable value changing means for changing a value of each of the plurality of variables displayed by the variable value displaying means to an arbitrary value; and the plurality of variable values changed by the variable value changing means and displayed by the variable value displaying means. Graph drawing means for drawing a graph corresponding to the expression data input by the expression input means in accordance with the value of each variable.

That is, in the graph display apparatus according to the first aspect of the present invention, arbitrary variable values are substituted for a plurality of variables included in the input expression data, and the variable values of the plurality of variables are substituted. Since the graph corresponding to the formula data is drawn, the ability of the graph analysis can be improved as compared with the case of drawing the graph by substituting and changing only the variable value for one variable.

A graph display device according to a second aspect of the present invention is the graph display device according to the first aspect, wherein the graph drawing means is displayed by the variable value display means by the variable value change means. Each time the value of each of the plurality of variables is changed to an arbitrary value, a graph corresponding to the expression data input by the expression input means is sequentially displayed according to the value of each of the plurality of changed and displayed variables. It is characterized by a graph drawing means for drawing.

That is, in the graph display device according to the second aspect of the present invention, each time the value of each of the plurality of variables included in the input formula data is changed to an arbitrary value, the plurality of changed variables are changed. Since the graphs corresponding to the input expression data are sequentially drawn according to the respective values, it is possible to dynamically display a graph in which a plurality of variables are changed to different arbitrary values.

According to a third aspect of the present invention, there is provided the graph display device according to the first or second aspect, wherein the variable value display means is input by the equation input means. Variable value display means is provided for displaying an increase or decrease in the value of each of a plurality of variables included in the expression data by the length of a bar.

That is, in the graph display device according to the third aspect of the present invention, the increase or decrease of the value of each of the plurality of variables included in the input formula data is indicated by the length of the bar. The substitution value, its numerical value, and its change state can be easily confirmed.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a configuration of an electronic circuit of an electronic computing device according to an embodiment of the graph display device of the present invention.

This electronic computer has a control unit (CPU) 11 composed of a computer or the like. Control unit (CP
U) 11, the recording medium reading unit 17 reads a system program stored in the ROM 13 in advance or a computer control program stored in the external recording medium 18 in advance in response to a key operation signal from the key input unit 12. The RAM 14 is used as a work memory to control the operation of each part of the circuit.

The control unit (CPU) 11 includes the key input unit 12, the ROM 13, the recording medium reading unit 17,
The AM 14 is connected, and the liquid crystal display unit 16 is connected via the display drive circuit 15.

The key input unit 12 is provided with data input keys 12a including various numerical / symbol key groups such as numerical keys, operator keys, and function keys, as well as variable expressions and functions of arbitrarily input coordinates. A graph mode for drawing and displaying figures and graphs by line segments on XY coordinates set on the liquid crystal display unit 16 according to formulas and the like, and a program for performing arithmetic control processing corresponding to arbitrarily input program data A mode selection screen G (see FIGS. 4 (A) and 6 (A)) having various operation modes such as a statistical mode for performing a statistical calculation process in accordance with a mode and arbitrarily input statistical data is displayed. A "menu" key 12b operated at the time of performing the operation, and an "execute" key 1 operated at the time of instructing the setting of the selected or inputted data or the execution of the calculation
2c, a "graph" key 12d operated when instructing the start of drawing / display processing of a figure or a graph according to the input expression, and a "graph" key 12d operated when instructing an arbitrary point on the displayed graph with a pointer "Trace" key 12e, "G ← → T" key 12f operated to switch the display state of the input formula data and the corresponding graph or graphic data, movement of the cursor on the display screen, data selection, variables "↑" cursor key 12g, which is operated when setting a value increase / decrease, etc.
"↓" cursor key 12h, "←" cursor key 12
i, a “→” cursor key 12j and the like.

The ROM 13 stores in advance system program data that governs the overall processing of the electronic circuit of the computer, and subprograms that govern the processing of various operation modes, such as the graph mode processing shown in FIG. Control program data, which is data, is also stored in advance.

The RAM 14 has a mode data memory M for storing mode data indicating the currently set operation mode, and the liquid crystal display 16 in the various operation modes.
A display data memory 19 in which display data to be displayed is developed and stored as bitmap pattern data.
A graphic coordinate data memory 20 for storing coordinate data indicating a start point and an end point of each line segment for creating a graphic combining a plurality of line segments, an input expression data memory 21 for storing input expression data, and an input expression Variable value data memories 22a, 22b,... Storing the substitution values for each variable included in the expression data stored in the data memory 21, and program data memory 2 storing the inputted program data
3. Coordinate data of each start point and end point for drawing a plurality of line segments stored in the graphic coordinate data memory 20, formula data stored in the input formula data memory 21, and variable value data memories 22a, 22b,. Graphic data and graph data created based on the substitution values of the variables contained in the stored input expression data are drawn in bitmap data and stored in the graph data memory 24, and in control processing of various operation modes. A data memory such as a work area 25 for temporarily storing data input and output by the control unit (CPU) 11 is provided.

Next, the operation of the electronic computer having the above configuration will be described. FIG. 2 is a flowchart showing the overall processing of the electronic computer. When a "menu" key 12b of the key input unit 12 is operated, a mode selection screen in which mode menus for selecting and setting operation modes such as a graph mode, a program mode, and a statistical mode [FIG.
(A) and FIG. 6 (A)] are displayed on the liquid crystal display unit 16 (steps S1 → S2).

In the display state of the mode selection screen,
When an arbitrary mode menu is selected by moving the cursor and operating the "execute" key 12c, mode data indicating the selected and specified operation mode is stored and set in the mode data memory M in the RAM 14, and the set operation mode is set. Is started and the initial display screen is displayed (steps S3 → S4, S5 → S6).
S7).

Such mode selection setting processing (step S)
1 to S7), when the graph mode is selected and set, an initial display screen for inputting coordinate data for drawing three-dimensional graph (graphic) data or formula data for drawing two-dimensional graph [ FIG. 4 (B) and FIG. 6 (B)
Is displayed on the liquid crystal display unit 16, and the graph mode process is activated (step S8 → SA).

When the program mode is selected and set by the mode selection setting process (steps S1 to S7), an initial display screen for inputting program data is displayed on the liquid crystal display section 16, and the program mode is set. The process is started (steps S9 → S10).

When the statistical mode is selected and set by the mode selection setting process (steps S1 to S7), an initial display screen for inputting statistical data is displayed on the liquid crystal display unit 16, and the statistical mode process is performed. Is started (steps S11 → S12).

When another operation mode is selected and set by the mode selection setting process (steps S1 to S7), the initial display screen is displayed on the liquid crystal display unit 16 and the corresponding operation mode is set. The processing is started (step S11 → other processing).

FIG. 3 is a flowchart showing the graph mode processing in the electronic computer. FIG. 4 is a view showing a data setting display state for drawing a three-dimensional graph (figure) accompanying the graph mode processing of the electronic computer.

FIG. 5 is a diagram showing a dynamic display state of a three-dimensional graph (figure) accompanying the graph mode processing of the electronic computer. As shown in FIG. 4A, by operating the “menu” key 12b of the key input unit 12, the operation mode selection screen G is displayed on the liquid crystal display unit 16 (steps S1 → S2). Cursor keys 12
“Graph” of the menu icon by the operation of g to 12j
Is selected and highlighted (step S3 → S4), and FIG.
As shown in (B), when the "execute" key 12c is operated, the operation mode of the CPU (control unit) 11 is set to the graph mode, and the graph mode processing is started, thereby forming the vertices of the three-dimensional graph (graphic). A coordinate number input screen G1 for inputting and setting the number of coordinates to be displayed is displayed as an initial screen (steps S5 → S6, S7, S8 → SA).

In the display state of the coordinate number input screen G1, as shown in FIG. 4B, the user operates the data input key 12a of the key input section 12 to select, for example, "4" which is the number of vertices of the triangular pyramid. 4C, the "execute" key 12c of the key input unit 12 is operated to store the coordinate data of the four vertices in the graphic coordinate data memory 20 in the RAM 14. Are secured, and a coordinate value input screen G2 for inputting the coordinate values of each vertex is displayed (steps A1 → A2).

In the display state of the coordinate value input screen G2, after the coordinate value data corresponding to each of the vertex symbols A, B, C, and D is input and displayed by the selection operation of the data input key 12a, As shown in FIG.
When the "execute" key 12c is operated, the coordinate value data of each of the input and displayed vertex coordinates A, B, C, D is stored in the coordinate memory area set and secured in the graphic coordinate data memory 20 in the RAM 14. A, B, C, and D are stored as coefficients of the vertex coordinates A, B, C, and D, and input expression data including variables s and t for changing the respective vertex coordinates. The coordinate change formula input screen G3 is displayed (step A1 → A2).

In the display state of the coordinate change expression input screen G3, the coordinate change expression for each of the vertex coordinates A, B, C, and D is represented by, for example, "t ² -1" for point A and is for "s ^t", with respect to the point C, "st + (t /
s) "and the point D are input and displayed as" s ² + t ² ", and as shown in FIG. 4E, when the" execute "key 12c is further operated, each coordinate is displayed. The change formulas are stored in the input formula data memory 21 in the RAM 14, and a variable initial value input screen G4 for initially setting variable values for the variables s and t included in each coordinate change formula.
Is displayed (step A1 → A2).

Here, the coordinate change equation will be described. The coordinate value of the vertex coordinates A input on the coordinate value input screen G2 in FIG. 4C is (7, 7, 0), and is input on the coordinate change expression input screen G3 in FIG. 4D. If the coordinate change equation for the vertex coordinates A is “t ² −1”, the equation representing the change characteristic of the point A is “(t ² −1) (7,7,0) = (7t ² −
7, 7t ² −7, 0) ”, and the coordinate value changes with the change in the value of the variable t.

Then, in the display state of the variable initial value input screen G4 in FIG. 4E, the data input key 12a of the key input section 12 is selectively operated, for example, to set the initial value "1" of the variable s to "1". When input as the initial value “1” of the variable t, the RAM substitutes the initial value of each variable data s, t as RAM.
14 are stored in variable data memories 22a and 22b (step A1 → A2).

In this way, the coordinate data (7, 7) corresponding to the vertices A, B, C, and D for drawing a three-dimensional graph (figure) accompanying the repetition of the steps A1 → A2
7, 0) are stored in the graphic coordinate data memory 20 and the change expressions A “t ² −1” and B “s
^t ”, C“ st + (t / s) ”and D“ s ² + t ² ”are stored in the input expression data memory 21, and further, the initial substitution value“ 1 ”of each of the variables s and t included in each change expression. Are stored in the variable data memories 22a and 22b, and FIG.
As shown in (A), when the "graph" key 12d of the key input unit 12 is operated, the expression data stored in the input expression data memory 21 in the RAM 14 has a form of "Y = X". It is determined whether or not it is a graph function (step A3 → A4).

[0033] Here, the formula data stored in the input expression data memory 21 in the RAM14 is, the coordinate-change "t ² -1", "s ^t" "st + (t / s)", "s ² +
When it is determined that the expression is not a graph function expression because of t ² ”, the four vertex coordinate data (7, 7, 0) stored in the graphic coordinate data memory 20 and the input expression data memory 21 are stored. Expression A “t” for each vertex coordinate
² -1 ", B" s ^t ", C" st + (t / s) ", D
“S ² + t ² ” and variable data memories 22a and 22b
Is stored in the graph data memory 2 based on the initial substitution value “1” of each of the variables s and t included in each change equation stored in the graph.
4 is a three-dimensional graph (in this case, a four-sided pyramid) connected by line segments having the start and end points between the four vertex coordinates A, B, C, and D on the coordinates set in the bit map memory area of No. 4 ) Is created and stored, written into the display data memory 19, and the liquid crystal display unit 1
6 (steps A4 → A5a, A6a).

At this time, the three-dimensional graph (figure) corresponding to the input equation data is displayed, and the variable s included in each coordinate change equation is set in parallel with the right end and the lower end of the display screen. Variable value display bars B1 and B2, which represent the substitution values of and t in a bar shape, are displayed (step A7).

The variable value display bars B1 and B2 are stored in the variable data memories 22a and 22b in the RAM 14, respectively.
The variable substitution value of the variable s and the variable substitution value of the variable t stored in the table are shown in a bar shape, as shown in FIG.
"↑" key 12g or "↓" key 12 of the key input unit 12
By the operation of h, the substitution value of the variable s stored in the variable data memory 22a is increased or decreased and the variable value display bar B1 is changed.
Are displayed (steps A8 → A9) and “→”
By the operation of the key 12j or the “←” key 12i, the substitution value of the variable t stored in the variable data memory 22b is increased or decreased and is displayed on the variable value display bar B2 (step A10 → A11).

Thus, each of the cursor keys "@" 12
By the selection operation of g to “→” 12j, the substitution value of the variable s stored in the variable data memory 22a and the substitution value of the variable t stored in the variable data memory 22b are respectively changed to arbitrary values. Each time the value is set, the substituted value that has been changed and set is converted into a change expression A “t ² −1” for each of the four vertex coordinates A, B, C, and D stored in the input expression data memory 21. , B "s ^t", C "st +
(T / s) ”and D“ s ² + t ² ”, and a three-dimensional graph (graphic) in which each vertex is moved and changed to a new coordinate position is drawn and created in the graph data memory 24 and rewritten. Dynamic display is performed on the display unit 16 (step A12 → A13).

Therefore, the two variables s and t included in each coordinate change equation for dynamically displaying the graphic data can be respectively arbitrarily changed in the variable value display bars B1 and B2 by operating the cursor keys. The values are changed to values, and then sequentially changed to corresponding graphic data, thereby enabling dynamic display.

In this case, when an intersection P with another graph data is detected, the coordinates of the intersection are calculated and displayed together (steps A14 → A15, A16). FIG. 6 is a view showing a data setting display state for two-dimensional graph drawing accompanying the graph mode processing of the electronic computer.

FIG. 7 is a diagram showing a dynamic display state of a two-dimensional graph accompanying the graph mode processing of the electronic computer. As shown in FIG. 6A, by operating the “menu” key 12 b of the key input unit 12, the operation mode selection screen G is displayed on the liquid crystal display unit 16 (steps S 1 → S 2). Cursor keys 12g-12j
By selecting "Graph" of the menu icon by the operation of (3) and inverting the display (Step S3 → S4), as shown in FIG.
(Control unit) The operation mode of the control unit 11 is set to the graph mode, the graph mode processing is started, and a function formula input screen G5 for inputting a graph function formula is displayed as an initial screen (steps S5 → S6, S7, S8 → SA).

In the display state of the function expression input screen G5, as shown in FIG. 6B, the user operates the data input key 12a of the key input unit 12 to select a function expression to be drawn as a graph, for example, by " After inputting "Y = AX + B", as shown in FIG. 6 (C), when the "execute" key 12c of the key input unit 12 is operated, the input function expression "Y =
AX + B ”is stored in the input expression data memory 21 in the RAM 14, and a variable initial value input screen G6 for initial setting of variable values for the variables A and B included in the function expression is displayed (step A1 → A2).

In the display state of the variable initial value input screen G6, the data input key 12a of the key input section 12 is selectively operated to, for example, set the initial value of the variable A to "2.254".
4 "and the initial value of the variable B" 1.147 ", the RAM 1
4 are stored in the variable data memories 22c and 22d (Step A1 → A2).

In this way, the graph function formula "Y = AX + B" is stored in the input formula data memory 21 with the repetition of the steps A1 → A2, and the initial values of the variables A and B included in the function formula are stored. Substitution value "2.254
4 "and" 1.147 "are stored in the variable data memories 22c and 22d.
When the "graph" key 12d of the key input unit 12 is operated as shown in FIG.
It is determined whether the function formula data stored in the input formula data memory 21 in M14 is a graph function formula in the form of “Y = X” (step A3 → A4).

Here, if the equation data stored in the input equation data memory 21 in the RAM 14 is determined to be a graph function equation because the function equation is “Y = AX + B”, the input The initial substitution values “2.2544” and “1” of the function formula “Y = AX + B” stored in the formula data memory 21 and the variables A and B included in the function formulas stored in the variable data memories 22c and 22d, respectively. .1
47 corresponding to the function formula “Y = 2.2544X + 1.147” on the coordinates set in the bitmap memory area of the graph data memory 24 based on “47”.
The dimensional graph is drawn and stored, written into the display data memory 19, and displayed on the liquid crystal display unit 16 (steps A4 → A5b, A6b).

At this time, the two-dimensional graph corresponding to the input function formula data is displayed, and the variables A and B included in the function formula are substituted in parallel with the right end and the lower end of the display screen. Variable value display bar B that represents the value as a bar
1 and B2 are displayed (step A7).

The variable value display bars B1 and B2 are stored in the variable data memories 22c and 22d in the RAM 14, respectively.
The variable substitution value of the variable A and the variable substitution value of the variable B stored in the table are shown in a bar shape, as shown in FIG.
"↑" key 12g or "↓" key 12 of the key input unit 12
By the operation of h, the substitution value of the variable A stored in the variable data memory 22c is increased or decreased and the variable value display bar B1 is changed.
Are displayed (steps A8 → A9) and “→”
By operating the key 12j or the “←” key 12i, the substitution value of the variable B stored in the variable data memory 22d is increased or decreased and is displayed correspondingly on the variable value display bar B2 (step A10 → A11).

Thus, each of the cursor keys “↑” 12
By the selection operation of g to “→” 12j, the substitution value of the variable A stored in the variable data memory 22c and the substitution value of the variable B stored in the variable data memory 22d are respectively changed to arbitrary values. In each case, the changed substituted value is substituted into the function formula “Y = AX + B” stored in the input formula data memory 21, and a new two-dimensional graph in which the graph coordinate position is moved and changed is set. The graph is drawn and created in the graph data memory 24, rewritten, and dynamically displayed on the liquid crystal display unit 16 (step A).
12 → A13).

In this case, when an intersection P with other graph data is detected, the coordinates of the intersection are calculated and displayed together in the intersection coordinate display area 26 (step A14 →
A15, A16).

Therefore, the two variables A and B included in the graph function for dynamically displaying the two-dimensional graph are displayed on the variable value display bars B1 and B2.
By operating the cursor keys, the values can be individually changed to arbitrary values, and sequentially changed to the corresponding graph data, thereby enabling dynamic display.

Thus, it is possible to easily analyze a complicated graph or a graphic (three-dimensional graph) in which a plurality of coordinate points change together. The method described in each of the above-described embodiments, that is, each method such as the overall processing of the electronic computer shown in the flowchart of FIG. 2 and the graph mode processing shown in the flowchart of FIG. , Memory card (RO
M card, RAM card, etc.), magnetic disk (floppy disk, hard disk, etc.), optical disk (CD-
External recording medium 1 such as ROM, DVD, and semiconductor memory
8 and can be distributed. Then, the computer reads the program recorded on the external recording medium 18 by the recording medium reading unit 17, and the operation is controlled by the read program so as to correspond to the two-variable change described in each of the embodiments. A dynamic graph display function can be realized, and the same processing by the above-described method can be executed.

[0050]

As described above, according to the graph display device of the first aspect of the present invention, an arbitrary variable value is substituted for each of a plurality of variables included in the input expression data, and Since the graph corresponding to the expression data in which each variable value is substituted is drawn, the graph analysis ability can be improved as compared with the case where the graph drawing is performed by substituting and changing only the variable value for one variable.

According to the graph display device of the second aspect of the present invention, each time the value of each of the plurality of variables included in the input formula data is changed to an arbitrary value, the changed plurality of variables are displayed. Since the graphs corresponding to the input expression data are sequentially drawn in accordance with the values of the variables, it becomes possible to dynamically display a graph in which a plurality of variables are changed to different arbitrary values.

Further, according to the graph display device of the third aspect of the present invention, the increase or decrease of the value of each of the plurality of variables included in the input formula data is displayed by the length of the bar. It becomes possible to easily confirm the substitution value of the variable, its numerical value, and its change state.

Therefore, according to the present invention, the corresponding graphics and graphs are sequentially displayed while the variable values of the plurality of variables included in the equation for drawing the line segment on the coordinates are individually changed to arbitrary values. It becomes possible to do.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an electronic circuit of an electronic computing device according to an embodiment of a graph display device of the present invention.

FIG. 2 is a flowchart showing the overall processing of the electronic computer.

FIG. 3 is a flowchart showing a graph mode process in the electronic computer.

FIG. 4 is a view showing a data setting display state for drawing a three-dimensional graph (graphic) accompanying the graph mode processing of the electronic computer.

FIG. 5 is a view showing a dynamic display state of a three-dimensional graph (figure) accompanying the graph mode processing of the electronic computer.

FIG. 6 is a view showing a data setting display state for drawing a two-dimensional graph accompanying the graph mode processing of the electronic computer.

FIG. 7 is a diagram showing a dynamic display state of a two-dimensional graph accompanying the graph mode processing of the electronic computing device.

[Explanation of symbols]

 11: control unit (CPU), 12: key input unit, 12a: data input key, 12b: "menu" key, 12c: "execute" key, 12d: "graph" key, 12g to 12j: cursor keys, 13 ... ROM, 14 RAM, 16 liquid crystal display unit, 17 recording medium reading unit, 18 external recording medium, 19 display data memory, 20 graphic coordinate data memory, 21 input data memory, 22a to 22d variables Data memory, 24: Graph data memory, 25: Work memory, 26: Intersection coordinate display area, G: Mode selection screen, G1: Coordinate number input screen, G2: Coordinate value input screen, G3: Coordinate change equation input screen, G4 , G6: Variable initial value input screen, G5: Function expression input screen, B1, B2: Variable value display bar.

Claims (5)

[Claims] An expression input means for inputting expression data including a plurality of variables for drawing a graph, and a variable for displaying respective values of the plurality of variables included in the expression data input by the expression input means Value display means; variable value change means for changing each of the plurality of variables displayed by the variable value display means to an arbitrary value; changed by the variable value change means and displayed by the variable value display means And a graph drawing means for drawing a graph corresponding to the expression data input by the expression input means in accordance with the values of the plurality of variables. 2. The graph drawing means, wherein each time a value of each of the plurality of variables displayed by the variable value display means is changed to an arbitrary value by the variable value changing means, the plurality of changed and displayed plural values are displayed. 2. The graph display device according to claim 1, wherein the graph display device is a graph drawing unit that sequentially draws a graph corresponding to the expression data input by the expression input unit according to the value of each variable. 3. The variable value display means is a variable value display means for displaying increase / decrease of the value of each of a plurality of variables included in the expression data input by the expression input means, using a bar length. The graph display device according to claim 1 or 2, wherein: 4. A variable value display step for displaying a value of each of a plurality of variables included in formula data for drawing a graph input by a formula input means, and the plurality of variables displayed in the variable value display step. A variable value changing step of changing the value of each of the variables to an arbitrary value; and changing the expression input according to the values of the plurality of variables changed in the variable value changing step and displayed in the variable value displaying step. A graph drawing step of drawing a graph corresponding to the expression data input by the means. 5. A variable value display means for displaying a value of each of a plurality of variables included in formula data for drawing a graph input by the formula input means, the computer displaying the variable value display means. A variable value changing unit that changes a value of each of the plurality of variables to an arbitrary value; and A recording medium that stores a graph display processing program for functioning as a graph drawing unit that draws a graph corresponding to the expression data input by the expression input unit.