JPH11143835A - Electronic computation device, graph display method and storage medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to simply display a graph indicating a function equation including a sum symbol. SOLUTION: A CPU 11 judges if a sum symbol is included in a function equation of an object for graph display stored in an equation register 14b and, when it is judged by this judgment that the sum symbol is included, a sum of the function equation from an initial value to a final value of a variable corresponding to the sum symbol is obtained, data for indicating a graph so as to indicate this sum is calculated, is stored in a graph register 14c and, at the same time, a display part 16 is made to display it. Also, a sum of each function equation is obtained for each value from the initial value to the final value of the variable corresponding to the sum symbol of the function equation, data for indicating the graph in order to indicate each sum is calculated, the graph register 14c (g1 to gn ) is made to store it and a graph corresponding to each value of the variable is made to selectively display it on the basis of these stored data.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic computer for displaying a graph based on a functional expression, a graph display method,
The present invention relates to a recording medium on which a graph display control program is recorded.

[0002]

2. Description of the Related Art Conventionally, in an electronic computer having a function calculating function, when a function formula is input and a display of a graph is instructed, a graph corresponding to the input function formula is displayed. I have.

In an electronic computer, for example, by specifying a plurality of numerical data and a function to be displayed in a graph, coordinate data for displaying a graph is calculated and set in advance. A graph is displayed in the XY coordinate range.

However, in a conventional electronic computer capable of displaying a graph, for example, a function formula including a sum symbol (Σ symbol) as shown in FIG. 4A, for example, a “Fourier transform” often used in the field of electric systems And a function expression representing a concept such as “Laplace transform” cannot be displayed as a graph.

For example, if the display of a graph is directly instructed for the function expression shown in FIG. 4A, a format error occurs for the function expression. Further, in order to prevent a format error, a graph display is performed after calculating a constant in the format of the summation symbol (定 数 symbol) in advance, or as shown in FIG. It is necessary to expand to a function expression equivalent to a function expression including and enter a mathematical expression for displaying a graph.

For example, as shown in FIG. 4B, by expanding a function expression including a summation symbol and instructing a graph display, a function expression including a summation symbol is obtained as shown in FIG. Can be displayed. That is,
The graph shown in FIG. 4C is a graph showing the sum of mathematical expressions at each value from the initial value n = 1 to the final value n = 10 for the variable n for the sum symbol of the function expression shown in FIG. It has become.

[0007]

As described above, in the conventional electronic computer, when displaying a graph of a function formula including a summation symbol, the summation symbol (Σ) is used in addition to the variables X and Y of the graph.
Cannot display the graph containing the variable n of the sum, and then display the graph after calculating the sum symbol format in advance and converting it to a constant, or expand it into a function formula equivalent to a function formula containing the sum symbol. Had to be displayed as a graph.

For this reason, for example, it is difficult to capture graph images representing concepts such as “Fourier transform” and “Laplace transform” which are often used in the field of electric systems, and f (n
In order to input a function expression expressed in the form of x) (n is a variable of a sum symbol), the function expression must be expanded as y = x + 2x + 3x +... + 10x, which takes a great deal of trouble. Had been lost.

The present invention has been made in view of the above circumstances, and has an electronic computer, a graph display method, and a graph display control program capable of easily displaying a graph representing a function expression including a summation symbol. It is intended to provide a recording medium on which is recorded.

[0010]

SUMMARY OF THE INVENTION The present invention relates to an electronic computing device for displaying a graph based on a function expression, and a determination means for determining whether or not the function expression to be displayed on the graph includes a sum symbol. And when the discriminating means determines that the summation symbol is included, obtains a summation of the functional expressions from an initial value to a final value of a variable for the summation symbol, and displays a graph representing the summation. Calculating means for calculating data, a graph storing means for storing the data calculated by the calculating means, and a graph representing a functional expression including a summation symbol based on the data stored by the graph storing means And a display means for displaying

According to such a configuration, even when the summation symbol is included in the function expression, the summation of the function expression from the initial value to the final value of the variable for the summation symbol is obtained.
Data for displaying the graph is calculated. Therefore,
This eliminates the need to pre-expand a function formula including the summation symbol into an equivalent function formula.

[0012] The calculating means may include, for each value from the initial value to the final value of the variable for the summation symbol of the function formula,
The sum of each of the functional expressions is determined, data for displaying a graph representing each sum is calculated and stored in the graph storage unit, and the display unit is stored in the graph storage unit. It is characterized in that a graph corresponding to each value of the variable for the sum symbol is selectively displayed.

According to such a configuration, not only the graph representing the sum from the initial value to the final value of the variable with respect to the sum symbol of the function formula including the sum symbol, but also the sum of the respective variables from the initial value to each value. Can be arbitrarily selected and displayed.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the system configuration of the electronic computer according to the present embodiment.
The electronic computer according to the present embodiment is, for example, a CD-RO
It is realized by a computer which reads a program recorded on a recording medium such as an M, DVD, or magnetic disk, and whose operation is controlled by the program.

As shown in FIG. 1, an electronic computer according to this embodiment includes a CPU 11, a key input unit 12, a ROM 1
3, a RAM 14, a display drive circuit 15, a display unit 16, and a recording medium reading unit 20.

The CPU 11 controls the overall operation of the apparatus. In response to a key operation signal from the key input unit 12, the CPU 11
A system program stored in advance in M13 is started, and a graph display process is executed according to the system program. The CPU 11 has a key input unit 1
2. In addition to the ROM 13, the RAM 14 is connected,
The display unit 16 is connected via the display drive circuit 15, and the recording medium reading unit 20 is connected.

Note that the CPU 11 is not limited to the program stored in the ROM 13, and may read the program recorded in the recording medium 21 by the recording medium reading unit 20 and store the program in the RAM 14 for execution.

The key input unit 12 is for inputting instructions and data for defining the operation of the apparatus, and includes numerical keys, character keys,
A data input key 12a including a symbol key and the like, a "graph" key 12b for displaying a graph of a function expression, and a cursor key 12c for performing various selections and designations are provided. Although not shown, it is assumed that various keys are provided in addition to the function keys for executing various functions.

The ROM 13 stores, in advance, a system processing program for controlling the entire electronic computer, a control processing program corresponding to various operation modes, and the like. RAM
Numeral 14 stores various data handled in the electronic computer, and includes a display register 14a, an expression register 14
b, a graph register 14c, and the like.

In the display register 14a, display data to be displayed on the display unit 16, for example, display data such as a function expression or a graph representing the function expression is developed and stored as bitmap data.

The expression register 14b stores data of a function expression for performing a function calculation. The data of the function expression stored in the expression register 14b is referred to when performing a graph display representing the function expression together with the function calculation processing. The function expression to be displayed in the graph can include a sum symbol (Σ symbol).

The graph register 14c is an expression register 14
The data of the graph corresponding to the function expression indicated by the data stored in b is stored. When the sum symbol is included, the sum of each value from the initial value to the final value of the function expression is calculated. The corresponding graph data is stored.

The display drive circuit 15 is controlled by the CPU 11 based on various data stored in the RAM 14 to
The display of a graph or the like on the display unit 16 is drive-controlled. The display unit 16 is composed of, for example, a liquid crystal display capable of color display, and performs various displays under the control of the display drive circuit 15.

The recording medium reading unit 20 writes / reads a program or data to / from the recording medium 21. As the recording medium 21, for example, various media such as a floppy disk, a hard disk, a CD-ROM, and a DVD can be used.

Next, the operation of the electronic computer according to this embodiment will be described with reference to the flowchart shown in FIG. First, when the system power supply of the electronic computer is turned on, the CPU 11 activates a control processing program stored in the ROM 13 to execute graph processing. In the graph processing, a function expression can be arbitrarily input, and a graph representing the function expression can be displayed on the display unit 16.

Here, when the data input key 12a of the key input section 12 is pressed, the CPU 11 inputs as data representing a function expression to be displayed in a graph,
(Steps S1, S1)
2).

In this embodiment, as shown in FIG. 3A, for example, it is assumed that a function expression including a sum symbol is input as a function expression to be displayed in a graph. The function expression shown in FIG. 3A is for obtaining the sum Y of the mathematical expression when the variable n for the sum symbol is set to each value from the initial value 1 to the final value 10.

As shown in FIG. 3A, when a "graph" key 12b of the key input unit 12 is pressed after a function expression to be displayed in a graph is input (step S11).
The CPU 11 starts displaying a graph representing the function expression stored in the expression register 14b.

The CPU 11 stores the expression register 1 in the RAM 14
With reference to the data representing the function expression stored in 4b, it is determined whether or not a sum symbol (Σ symbol) is included (step S12). If it is determined that the function expression does not include the summation symbol, the CPU 11 calculates coordinate data for displaying a graph corresponding to the input function expression and stores the coordinate data in the graph register 14c of the RAM 14. (Step S13).

The CPU 11 controls the display drive circuit 15
Based on the graph data stored in the graph register 14c, a graph representing a function expression is displayed on the display unit 16 (step S14).

On the other hand, if it is determined that the function expression includes the summation symbol, the CPU 11 substitutes an initial value 1 for a variable n added to the summation symbol for the input function expression, and The coordinate data for displaying the corresponding graph is calculated, and the graph register 14c (g1) of the RAM 14 is calculated.
(Step S3).

In the example of the function formula shown in FIG.
The coordinate data of the graph of y = 1 / n (sin x) at the time of is stored. Further, the CPU 11 calculates the sum Y of the function formulas.
The coordinate data of the graph is set as g1 for the subsequent processing for calculating the graph (step S4).

Next, the CPU 11 adds 1 to the value of the variable n of the function expression to update it (step S5), and updates the updated n.
And the coordinate data for displaying the graph according to the function formula is calculated (step S6). That is, in the example of the function expression shown in FIG. 3A, when n = 2, y = 2 /
The coordinate data of the graph of n (sin 2x) is calculated and obtained.

The CPU 11 adds the coordinate data of the graph at the time when the variable n is 2 to the coordinate data g1 set in the preceding process, and sets the result as g2 (step S7). The CPU 11 also calculates the coordinate data g2 of the graph.
Is stored in the graph register 14c (g2) of the RAM 14 (step S8). Therefore, the graph register 14c
The coordinate data g2 stored in (g2) is y = 1 / n
This is data representing a graph of a function formula of (sin x) + 2 / n (sin 2x).

Here, if the value of the variable n added to the summation symbol is not the specified value (10 in the example shown in FIG. 3A), the CPU 11 returns to the processing of step S5 and The value of the variable n in the expression is updated by adding 1, and thereafter, the same processing as described above is executed.

Accordingly, by repeatedly executing the above-described processing up to the final value designated for the variable n, the data of the graph of the function formula for each value from the initial value (1) to the final value (10) is obtained. The graph register 14c (g1
To g10).

When the processing up to the final value of the variable n is performed (step S9), the CPU 11 renders the graph at the final value (10), that is, the graph representing the function formula including the summation symbol, into the display drive circuit 15 Thus, a graph representing a functional expression is displayed on the display unit 16 based on the graph data stored in the graph register 14c (g10) (step S10). FIG. 3B shows a display example of a graph representing the function formula shown in FIG. FIG.
In the example shown in (b), the value of the variable n (n = 10) is displayed together.

Further, in the electronic computer according to the present embodiment, as shown in FIG. 3B, when a graph representing the sum Y of the function formulas is displayed, a graph corresponding to each value of the variable n is displayed. Can be changed.

When the cursor key 12c of the key input section 12 is pressed in the state shown in FIG.
For example, when the cursor key indicates an upward direction or a downward direction, it is determined whether or not the RAM 14 stores graph data (g1 to g10) relating to a function expression including a summation symbol (step S16).

Here, if a graph is stored, C
The PU 11 reads the data of the graph according to the instruction by the cursor key (step S17), and the display drive circuit 1
5 is displayed together with the value of the variable n on the display unit 16 (step S18).

For example, when the cursor key indicating the downward direction is assigned to instruct the display of the graph in which the value of the variable n is small, the downward direction is displayed while the graph when the variable n = 10 is displayed. Can be switched to the graph display when the variable n = 9.

Similarly, by pressing the down cursor key an arbitrary number of times, a graph for each variable value can be displayed. FIGS. 3C, 3D, and 3E show states where graphs are displayed when n = 5, n = 3, and n = 1, respectively.

Conversely, if the upward cursor key is assigned to instruct the display of a graph having a large value of the variable n, pressing the upward cursor key causes the current display to be performed. The display can be switched to a graph of a value next to the value of the variable n corresponding to the current graph.

As described above, in the electronic computing device according to the present embodiment, even if the function formula includes the summation symbol, the format of the summation symbol is calculated in advance and converted into a constant, or the same as the function formula including the summation symbol. Since the graph can be displayed as it is without expanding to the above equation, no labor is required and the work load can be reduced.

The sum Y up to the final value of the variable n added to the sum symbol (n = 10 in the example shown in FIG. 3A)
In addition to the graph, the graph at each value from the initial value to the final value can be displayed by an arbitrary instruction by operating the cursor key 12c, for example. Therefore, for example, a graph image such as “Fourier transform” or “Laplace transform” used in the field of electric systems can be easily grasped.

The above-described processing can be provided as a program that can be executed by a computer by recording the program on a recording medium such as a magnetic disk, an optical disk, and a semiconductor memory. A computer that realizes the present apparatus reads the program recorded on the recording medium, and executes the above-described processing by controlling the operation of the program.

[0047]

As described above in detail, according to the present invention, it is determined whether or not a summation symbol is included in a function expression to be displayed in a graph, and by this determination, it is determined that the summation symbol is included. In this case, the sum of the function formula from the initial value to the final value of the variable for the sum symbol is obtained, data for displaying a graph representing the sum is calculated, and the sum symbol is calculated based on the calculated data. Can be displayed as a graph that represents a function expression that includes the summation symbol, so even if it is a function expression that includes the summation symbol, it is calculated in advance in the format of the summation symbol and converted into a constant, or an expression equivalent to the function expression that includes the summation symbol The graph can be displayed as it is without expanding the data, and the work load can be reduced.

Further, for each value from the initial value to the final value of the variable for the sum symbol of the function formula, the sum of each function formula is obtained, and data for displaying a graph representing each sum is calculated. Since it is possible to memorize and selectively display a graph corresponding to each value of the variable for the stored sum symbol, it is easy to grasp the change of the graph representing the function formula due to the difference in the variable value for the sum symbol. Can be.

[Brief description of the drawings]

FIG. 1 is an exemplary block diagram showing the system configuration of an electronic computing device according to an embodiment of the present invention.

FIG. 2 is a flowchart for explaining the operation of a graph display process of the electronic computer according to the embodiment.

FIG. 3 is a view for explaining a specific example of graph display according to the embodiment.

FIG. 4 is a diagram for explaining a specific example of a conventional graph display.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... CPU11 12 ... Key input part 13 ... ROM14 ... RAM15 ... Display drive circuit 16 ... Display part 20 ... Recording medium reading part 21 ... Recording medium

Claims (5)

[Claims] 1. An electronic computing device for displaying a graph based on a function expression, wherein a discriminating means for discriminating whether or not the function expression to be displayed on the graph includes a summation symbol; When it is determined that is included, calculating means for calculating the sum of the functional formula from the initial value to the final value of the variable for the sum symbol, and calculating data for displaying a graph representing the sum, Graph storage means for storing the data calculated by the calculation means, and display means for displaying a graph representing a function expression including a summation symbol based on the data stored by the graph storage means. An electronic computing device, comprising: 2. The calculating means obtains the sum of the function formulas for each value from the initial value to the final value of the variable for the sum symbol of the function formula, and displays a graph representing the sum of the function formulas. Calculating the data for the sum, and storing the calculated data in the graph storage means.The display means selectively displays a graph corresponding to each value of the variable for the sum symbol stored in the graph storage means. The electronic computing device according to claim 1, wherein: 3. A graph display method for displaying a graph based on a function expression, wherein it is determined whether or not the function expression to be displayed on the graph includes a summation symbol. If it is determined that the sum has been calculated, the sum of the function formula from the initial value to the final value of the variable for the sum symbol is calculated, and data for displaying a graph representing the sum is calculated. A graph representing a function expression including a summation symbol based on the graph. 4. For each value from the initial value to the final value of a variable for the sum symbol of the function formula, obtain the sum of each of the function formulas, and calculate data for displaying a graph representing each sum. 4. The graph display method according to claim 3, wherein a graph corresponding to each value of a variable for the stored sum symbol is selectively displayed. 5. A computer determines whether or not a summation symbol is included in a function expression to be displayed in a graph, and when it is determined that the summation symbol is included in the function expression, a variable of the variable corresponding to the summation symbol is determined. A total sum of the functional expressions from an initial value to a final value is obtained, data for displaying a graph representing the total is calculated, and a graph representing a functional expression including a sum symbol is calculated based on the calculated data. A computer-readable recording medium on which a program for causing a computer to function as a computer is displayed.