Error parse error octave

Октава сообщает о двух видах ошибок для некорректных программ.

Октава сообщает о двух видах ошибок для некорректных программ.

Ошибка синтаксического анализа возникает, если Octave не может понять что-то, что вы набрали. Например, если вы неправильно написали ключевое слово,

octave:13> function z = f (x, y) z = x ||| 2; endfunction

Октава немедленно ответит таким сообщением:

parse error:

  syntax error

>>> function z = f (x, y) z = x ||| y; endfunction
                                  ^

Для большинства ошибок разбора Octave использует каретку (‘^‘), чтобы отметить точку на линии, где он не смог понять ваш ввод. В этом случае Octave сгенерировал сообщение об ошибке, потому что ключевое слово для логического или оператора ( || ) было написано с ошибкой. Он отметил ошибку на третьем ‘|‘ потому что код, ведущий к этому, был правильным, но окончательным ‘|‘ не было понято.

Другой класс сообщений об ошибках возникает во время оценки. Эти ошибки называются ошибками времени выполнения или иногда ошибками оценки , потому что они возникают, когда ваша программа выполняется или оценивается . Например, если после исправления ошибки в предыдущем определении функции вы наберете

octave:13> f ()

Октава ответит

error: `x
error: called from:
error:   f at line 1, column 22

Это сообщение об ошибке состоит из нескольких частей и дает довольно много информации,которая поможет вам найти источник ошибки.Сообщения генерируются из точки самой сокровенной ошибки и обеспечивают трассировку вложенных выражений и вызовов функций.

В приведенном выше примере первая строка указывает,что переменная с именем ‘x‘ оказалось неопределенным рядом со строкой 1 и столбцом 24 какой-то функции или выражения. Для ошибок, возникающих внутри функций, строки отсчитываются от начала файла, содержащего определение функции. Для ошибок, возникающих за пределами объемлющей функции, номер строки указывает номер входной строки, который обычно отображается в основной строке подсказки.

Вторая и третья строки сообщения об ошибке указывают, что ошибка произошла в функции f . Если бы функция f была вызвана из другой функции, например g , список ошибок закончился бы еще одной строкой:

error:   g at line 1, column 17

Эти списки вызовов функций позволяют довольно легко проследить путь,пройденный вашей программой до возникновения ошибки,и исправить ошибку перед повторной попыткой.

Содержание

  1. Parse error near line octave
  2. Parse error near line octave
  3. Parse error near line octave
  4. Parse error near line octave
  5. Parse error near line octave

Parse error near line octave

Octave reports two kinds of errors for invalid programs.

A parse error occurs if Octave cannot understand something you have typed. For example, if you misspell a keyword,

Octave will respond immediately with a message like this:

For most parse errors, Octave uses a caret (‘ ^ ’) to mark the point on the line where it was unable to make sense of your input. In this case, Octave generated an error message because the keyword for the logical or operator ( || ) was misspelled. It marked the error at the third ‘ | ’ because the code leading up to this was correct but the final ‘ | ’ was not understood.

Another class of error message occurs at evaluation time. These errors are called run-time errors, or sometimes evaluation errors, because they occur when your program is being run, or evaluated. For example, if after correcting the mistake in the previous function definition, you type

Octave will respond with

This error message has several parts, and gives quite a bit of information to help you locate the source of the error. The messages are generated from the point of the innermost error, and provide a traceback of enclosing expressions and function calls.

In the example above, the first line indicates that a variable named ‘ x ’ was found to be undefined near line 1 and column 24 of some function or expression. For errors occurring within functions, lines are counted from the beginning of the file containing the function definition. For errors occurring outside of an enclosing function, the line number indicates the input line number, which is usually displayed in the primary prompt string.

The second and third lines of the error message indicate that the error occurred within the function f . If the function f had been called from within another function, for example, g , the list of errors would have ended with one more line:

These lists of function calls make it fairly easy to trace the path your program took before the error occurred, and to correct the error before trying again.

Источник

Parse error near line octave

Octave reports two kinds of errors for invalid programs.

A parse error occurs if Octave cannot understand something you have typed. For example, if you misspell a keyword,

Octave will respond immediately with a message like this:

For most parse errors, Octave uses a caret (‘ ^ ’) to mark the point on the line where it was unable to make sense of your input. In this case, Octave generated an error message because the keyword for the logical or operator ( || ) was misspelled. It marked the error at the third ‘ | ’ because the code leading up to this was correct but the final ‘ | ’ was not understood.

Another class of error message occurs at evaluation time. These errors are called run-time errors, or sometimes evaluation errors, because they occur when your program is being run, or evaluated. For example, if after correcting the mistake in the previous function definition, you type

Octave will respond with

This error message has several parts, and gives quite a bit of information to help you locate the source of the error. The messages are generated from the point of the innermost error, and provide a traceback of enclosing expressions and function calls.

In the example above, the first line indicates that a variable named ‘ x ’ was found to be undefined near line 1 and column 24 of some function or expression. For errors occurring within functions, lines are counted from the beginning of the file containing the function definition. For errors occurring outside of an enclosing function, the line number indicates the input line number, which is usually displayed in the primary prompt string.

The second and third lines of the error message indicate that the error occurred within the function f . If the function f had been called from within another function, for example, g , the list of errors would have ended with one more line:

These lists of function calls make it fairly easy to trace the path your program took before the error occurred, and to correct the error before trying again.

Источник

Parse error near line octave

Octave reports two kinds of errors for invalid programs.

A parse error occurs if Octave cannot understand something you have typed. For example, if you misspell a keyword,

Octave will respond immediately with a message like this:

For most parse errors, Octave uses a caret (‘ ^ ’) to mark the point on the line where it was unable to make sense of your input. In this case, Octave generated an error message because the keyword for the logical or operator ( || ) was misspelled. It marked the error at the third ‘ | ’ because the code leading up to this was correct but the final ‘ | ’ was not understood.

Another class of error message occurs at evaluation time. These errors are called run-time errors, or sometimes evaluation errors, because they occur when your program is being run, or evaluated. For example, if after correcting the mistake in the previous function definition, you type

Octave will respond with

This error message has several parts, and gives quite a bit of information to help you locate the source of the error. The messages are generated from the point of the innermost error, and provide a traceback of enclosing expressions and function calls.

In the example above, the first line indicates that a variable named ‘ x ’ was found to be undefined near line 1 and column 24 of some function or expression. For errors occurring within functions, lines are counted from the beginning of the file containing the function definition. For errors occurring outside of an enclosing function, the line number indicates the input line number, which is usually displayed in the primary prompt string.

The second and third lines of the error message indicate that the error occurred within the function f . If the function f had been called from within another function, for example, g , the list of errors would have ended with one more line:

These lists of function calls make it fairly easy to trace the path your program took before the error occurred, and to correct the error before trying again.

Источник

Parse error near line octave

Octave reports two kinds of errors for invalid programs.

A parse error occurs if Octave cannot understand something you have typed. For example, if you misspell a keyword,

Octave will respond immediately with a message like this:

For most parse errors, Octave uses a caret (‘ ^ ’) to mark the point on the line where it was unable to make sense of your input. In this case, Octave generated an error message because the keyword for exponentiation ( ** ) was misspelled. It marked the error at the third ‘ * ’ because the code leading up to this was correct but the final ‘ * ’ was not understood.

Another class of error message occurs at evaluation time. These errors are called run-time errors, or sometimes evaluation errors, because they occur when your program is being run, or evaluated. For example, if after correcting the mistake in the previous function definition, you type

Octave will respond with

This error message has several parts, and gives quite a bit of information to help you locate the source of the error. The messages are generated from the point of the innermost error, and provide a traceback of enclosing expressions and function calls.

In the example above, the first line indicates that a variable named ‘ x ’ was found to be undefined near line 1 and column 24 of some function or expression. For errors occurring within functions, lines are counted from the beginning of the file containing the function definition. For errors occurring outside of an enclosing function, the line number indicates the input line number, which is usually displayed in the primary prompt string.

The second and third lines of the error message indicate that the error occurred within the function f . If the function f had been called from within another function, for example, g , the list of errors would have ended with one more line:

These lists of function calls make it fairly easy to trace the path your program took before the error occurred, and to correct the error before trying again.

Источник

Parse error near line octave

Octave reports two kinds of errors for invalid programs.

A parse error occurs if Octave cannot understand something you have typed. For example, if you misspell a keyword,

Octave will respond immediately with a message like this:

For most parse errors, Octave uses a caret (‘ ^ ’) to mark the point on the line where it was unable to make sense of your input. In this case, Octave generated an error message because the keyword for exponentiation ( ** ) was misspelled. It marked the error at the third ‘ * ’ because the code leading up to this was correct but the final ‘ * ’ was not understood.

Another class of error message occurs at evaluation time. These errors are called run-time errors, or sometimes evaluation errors, because they occur when your program is being run, or evaluated. For example, if after correcting the mistake in the previous function definition, you type

Octave will respond with

This error message has several parts, and gives quite a bit of information to help you locate the source of the error. The messages are generated from the point of the innermost error, and provide a traceback of enclosing expressions and function calls.

In the example above, the first line indicates that a variable named ‘ x ’ was found to be undefined near line 1 and column 24 of some function or expression. For errors occurring within functions, lines are counted from the beginning of the file containing the function definition. For errors occurring outside of an enclosing function, the line number indicates the input line number, which is usually displayed in the primary prompt string.

The second and third lines of the error message indicate that the error occurred within the function f . If the function f had been called from within another function, for example, g , the list of errors would have ended with one more line:

These lists of function calls make it fairly easy to trace the path your program took before the error occurred, and to correct the error before trying again.

Источник

Octave reports two kinds of errors for invalid programs.

A parse error occurs if Octave cannot understand something you have typed. For example, if you misspell a keyword,

octave:13> function y = f (x) y = x***2; endfunction

Octave will respond immediately with a message like this:

parse error:

  syntax error

>>> function y = f (x) y = x***2; endfunction
                              ^

For most parse errors, Octave uses a caret (‘^’) to mark the point on the line where it was unable to make sense of your input. In this case, Octave generated an error message because the keyword for exponentiation (**) was misspelled. It marked the error at the third ‘*’ because the code leading up to this was correct but the final ‘*’ was not understood.

Another class of error message occurs at evaluation time. These errors are called run-time errors, or sometimes evaluation errors, because they occur when your program is being run, or evaluated. For example, if after correcting the mistake in the previous function definition, you type

octave:13> f ()

Octave will respond with

error: `x' undefined near line 1 column 24
error: called from:
error:   f at line 1, column 22

This error message has several parts, and gives quite a bit of information to help you locate the source of the error. The messages are generated from the point of the innermost error, and provide a traceback of enclosing expressions and function calls.

In the example above, the first line indicates that a variable named ‘x’ was found to be undefined near line 1 and column 24 of some function or expression. For errors occurring within functions, lines are counted from the beginning of the file containing the function definition. For errors occurring outside of an enclosing function, the line number indicates the input line number, which is usually displayed in the primary prompt string.

The second and third lines of the error message indicate that the error occurred within the function f. If the function f had been called from within another function, for example, g, the list of errors would have ended with one more line:

error:   g at line 1, column 17

These lists of function calls make it fairly easy to trace the path your program took before the error occurred, and to correct the error before trying again.

© 1996–2020 John W. Eaton
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Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one.
Permission is granted to copy and distribute translations of this manual into another language, under the above conditions for modified versions.
https://octave.org/doc/v5.2.0/Errors.html

Кажется, это ошибка разбора/синтаксиса для моей системы ODE, особенно для xdot(2). Но я не могу понять

Я проверил аналогичный вопрос в StackOverflow, но не нашел своего решения.

function xdot = f3(x, t)
      xdot =zeros(2, 1);
      x=zeros(1, 2);

      r_1=4;
      R_1=1;
      p_1=8;
      l_1=0.2;
      r_2=10;
      p_2=10;
      R_2=2;
      l_2=50;
      rM= 0.01;
      d=2;

      xdot(1)= ((r_1*p_1*x(3))/(1+p_1*x(3)))*x(1)-r_1*x(1)^2-(R-1*x(1))/(1+r_1*x(3)-x(1)*x(2)
      xdot(2)= rM + ((r_2*p_2*x(3))/(1+p_2*x(3)))*x(2)-r_2*x(2)^2-(R_2*x(2))/(1+p_2*x(3))
      xdot(3)= d - (l_1*r_1*x(1))/(1+p_1*x(2))-(l_2*r_2*x(2)/(1+r_2*x(3))
endfunction

x0 = [1; 0; -1];
t = linspace(0, 2, 201);
x = lsode (@f3, x0, t);

figure(1);
plot(t, x(:,1));
xlabel('t');
ylabel('X');
title('X - component');


figure(2);
plot(t, x(:,2));
xlabel('t');
ylabel('Y');
title('Y - component');

Должен решить системную оду, но давая мне

f3

parse error near line 18 of file C:/Users/Admin/Desktopf3.m

syntax error

>>>   xdot(2)= rM + ((r_2*p_2*x(3))/(1+p_2*x(3)))*x(2)-r_2*x(2)^2- 
(R_2*x(2))/(1+p_2*x(3))

     ^

Перейти к ответу
Данный вопрос помечен как решенный


Ответы
2

Похоже, там несколько проблем.

  1. Вы создаете значения xdot и x размера 2, но получаете доступ/устанавливаете индекс 3.

  2. Для xdot(1)= ((r_1*p_1*x(3))/(1+p_1*x(3)))*x(1)-r_1*x(1)^2-(R-1*x(1))/(1+r_1*x(3)-x(1)*x(2)

    А) Вы пропустили ‘)’, что вызывает синтаксическую ошибку.

    B) R-1is неверен — у вас нет буквы «R», поэтому, вероятно, это должно быть R_1

  3. В xdot(3)= d — (l_1*r_1*x(1))/(1+p_1*x(2))-(l_2*r_2*x(2)/(1+r_2*x(3)) вам не хватает ‘)’

С функцией производных

function xdot = f3(x, t)
      xdot = 0*x;

      r_1=4;
      R_1=1;
      p_1=8;
      l_1=0.2;
      r_2=10;
      p_2=10;
      R_2=2;
      l_2=50;
      rM= 0.01;
      d=2;

      xdot(1)= ((r_1*p_1*x(3))/(1+p_1*x(3)))*x(1)-r_1*x(1)^2-(R_1*x(1))/(1+r_1*x(3)-x(1)*x(2));
      xdot(2)= rM + ((r_2*p_2*x(3))/(1+p_2*x(3)))*x(2)-r_2*x(2)^2-(R_2*x(2))/(1+p_2*x(3));
      xdot(3)= d - (l_1*r_1*x(1))/(1+p_1*x(2))-(l_2*r_2*x(2)/(1+r_2*x(3)));
end

Который исправляет все ошибки, упомянутые в комментариях и обобщенные в ответе @lostbard, я получаю решение для части интервала. Решение взрывается в компоненте X для t около 0.3295, что также видно на полученном графике.

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