只执行了部分代码，不显示任何错误信息

Question

我在 Mac OS 上使用 MATLAB 2020 Psychtoolbox，每次我运行这段代码时，它们的屏幕都会变灰，然后是错误声音，但是，没有显示任何错误消息在命令 window 中。如何执行所有代码？

% Clear the workspace
close all;
clearvars;
sca;

% Setup PTB with some default values
PsychDefaultSetup(2);

% Seed the random number generator. Here we use the an older way to be
% compatible with older systems. Newer syntax would be rng('shuffle'). Look
% at the help function of rand "help rand" for more information
rand('seed', sum(100 * clock));

  % Set the screen number to the external secondary monitor if there is one
% connected
screenNumber = max(Screen('Screens'));

% Define white, grey and black
white = WhiteIndex(screenNumber);
grey = white / 2;
black = BlackIndex(screenNumber);

% Open an on screen window
[window, windowRect] = PsychImaging('OpenWindow', screenNumber, grey);

% Get the size of the on screen window
[screenXpixels, screenYpixels] = Screen('WindowSize', window);

% Query the frame duration
ifi = Screen('GetFlipInterval', window);

% Set up alpha-blending for smooth (anti-aliased) lines
Screen('BlendFunction', window, 'GL_SRC_ALPHA', 'GL_ONE_MINUS_SRC_ALPHA');

% Setup the text type for the window
Screen('TextFont', window, 'Ariel');
Screen('TextSize', window, 36);

% Get the centre coordinate of the window
[xCenter, yCenter] = RectCenter(windowRect);


%----------------------------------------------------------------------
%                       Keyboard information
%----------------------------------------------------------------------

% Define the keyboard keys that are listened for. We will be using the left
% and right arrow keys as response keys for the task and the escape key as
% a exit/reset key
escapeKey = KbName('ESCAPE');
leftKey = KbName('LeftArrow');
rightKey = KbName('RightArrow');
downKey = KbName('DownArrow');

%----------------------------------------------------------------------
%                       Fixation cross
%----------------------------------------------------------------------

% Here we set the size of the arms of our fixation cross
fixCrossDimPix = 10;

% Now we set the coordinates (these are all relative to zero we will let
% the drawing routine center the cross in the center of our monitor for us)
xCoords = [-fixCrossDimPix fixCrossDimPix 0 0];
yCoords = [0 0 -fixCrossDimPix fixCrossDimPix];
allCoords = [xCoords; yCoords];

% Set the line width for our fixation cross
lineWidthPix = 4;

%----------------------------------------------------------------------
%                            Colors
%----------------------------------------------------------------------

% We are going to use three colors for this demo. Red, Green and blue.
wordList = {'Green', 'Magenta', 'Orange'};
Colors = [0 1 0; 1 0 1; 0.8500 0.3250 0.0980];

%----------------------------------------------------------------------
%                  Define positions of sequences
%----------------------------------------------------------------------

leftX = screenXpixels/2.5;
leftY = screenXpixels/1.6;
rightX = screenXpixels/1.7;
rightY = screenYpixels/1.6;
upX = screenXpixels/2.1;
upY = screenYpixels/2.6;

left = [leftX leftY];
right = [rightX rightY];
up = [upX upY];

%----------------------------------------------------------------------
%                  Randomise temporal order of trials
%----------------------------------------------------------------------
 
trialorder = [1 0 0 0 0];
randtemp = shuffle(trialorder);

%----------------------------------------------------------------------
%                           Trial loop
%----------------------------------------------------------------------
nTrials = 5;

for trial = 1:randtemp
    
    % randomise position of sequences
    randpos = shuffle(left, right, up);
    
    % fixation cross
    % Draw the fixation cross in white, set it to the center of our screen and
    % set good quality antialiasing
    Screen('DrawLines', window, allCoords,...
    lineWidthPix, white, [xCenter yCenter], 2);

    % Derive distributions
    seq1 = distribution(0.02, 0.126, 0.146, 0.106, 5); % high variance
    seq2 = distribution(0.02, 0.126, 0.146, 0.106, 5); % low variance
    seq3 = distribution(0.02, 0.126, 0.146, 0.106, 5); % low variance
    
    seq4 = distribution(0.02, 0.126, 0.146, 0.106, 5);
    seq5 = distribution(0.02, 0.126, 0.146, 0.106, 5);
    seq6 = distribution(0.02, 0.126, 0.146, 0.106, 5);
    
    seq7 = distribution(0.02, 0.126, 0.146, 0.106, 5);
    seq8 = distribution(0.02, 0.126, 0.146, 0.106, 5);
    seq9 = distribution(0.02, 0.126, 0.146, 0.106, 5);
    
    seq10 = distribution(0.02, 0.126, 0.146, 0.106, 5);
    seq11 = distribution(0.02, 0.126, 0.146, 0.106, 5);
    seq12 = distribution(0.02, 0.126, 0.146, 0.106, 5);
    
    seq13 = distribution(0.02, 0.126, 0.146, 0.106, 5);
    seq14 = distribution(0.02, 0.126, 0.146, 0.106, 5);
    seq15 = distribution(0.02, 0.126, 0.146, 0.106, 5);

    if trial == 1 
       DrawFormattedText(window, 'Name the color \n\n Press Any Key To Begin',...
       'center', 'center', black);
       Screen('Flip', window);
       KbStrokeWait;
    end
    
    if randtemp() == 0
        % trail 1
        Screen('DrawText', num2str(seq1), white, randpos(1));
        Screen('DrawText', num2str(seq2), white, randpos(2));
        Screen('DrawText', num2str(seq3), white, randpos(3));
        WaitSecs(0.75)
        Screen('Flip', window);
        KbStrokeWait;
           
        Screen('DrawText', num2str(seq2), white, randpos(1));
        Screen('DrawText', num2str(seq3), white, randpos(2));
        WaitSecs(0.75)
        Screen('Flip', window);
        KbStrokeWait;
        
        %trial 2
        %repeat
        
    else 
        Screen('DrawText', num2str(seq13), white, randpos(1));
        Screen('DrawText', num2str(seq14), white, randpos(2));
        Screen('DrawText', num2str(seq15), white, randpos(3));
        WaitSecs(0.75)
        Screen('Flip', window);
        KbStrokeWait;
           
        Screen('DrawText', num2str(seq13), white, randpos(1));
        Screen('DrawText', num2str(seq14), white, randpos(2));
        WaitSecs(0.75)
        Screen('Flip', window);
        KbStrokeWait;
    end
end       

        

      

% Flip to the screen
Screen('Flip', window);

% Wait for a key press
KbStrokeWait;

% Clear the screen
sca

'distribution'函数是一个自制函数，生成具有指定均值、方差、上限、下限和给定数量的随机数的高斯分布：

function distribution(va, mu, ul, ll, nvals)
 multiplier=10;
 x = mu + randi(multiplier*nvals,1)*sqrt(va); % Generate sufficient random numbers
 idx = (ll <= x) & (x <= ul); % Extract the value in the given range [min max]
 while sum(idx)<nvals
    multiplier=multiplier+1;
    x = mu + randi(multiplier*nvals,1)*sqrt(va); % Generate sufficient random numbers
    idx = (ll <= x) & (x <= ul); % Extract the value in the given range [min max]
 end
 x = x(idx);
 x = x(1:nvals); % Extract numbers

Answer 1

您只看到灰色屏幕，因为该错误不会导致 Psychtoolbox window（您已将其设置为灰色背景）关闭。要关闭屏幕并显示错误，请将代码包装在 try、catch 语句中，如果遇到错误，它将关闭屏幕并重新抛出错误。

例如（这里的CODE这个词只是一个占位符，而不是用你的实际代码替换它）

try
    CODE
catch e
    sca;
    rethrow(e)
end

在这种情况下，如果在 try 语句的主体内遇到错误，它将转到 catch 语句，调用错误 e。首先屏幕将用 sca 关闭，然后通过 rethrow.

实际显示错误

就您遇到的实际错误而言，我认为您当前的代码至少存在一些问题：

Psychtoolbox 中的 Shuffle 函数大写 - 'Shuffle' 和有一个输入。在这里，您使用 'shuffle'，并提供三个独立的输入。

不是提供 'left'、'right' 和 'up' 作为单独的输入，将它们组合成单个元胞数组的元素：

正在替换：randpos = shuffle(left, right, up);

与：randpos = Shuffle({left, right, up});

和 select 它们作为元胞数组的元素：

正在替换：Screen('DrawText', num2str(seq1), white, randpos(1));

与：Screen('DrawText', window, num2str(seq1), white, [], black, randpos{1}(1), randpos{1}(2));
在您定义的分布函数中，您没有包含输出参数。将您当前的第一个函数行替换为：function x = distribution(va, mu, ul, ll, nvals)
KbStrokeWait 只检查连接的第一个键盘。例如，如果您在笔记本电脑上使用外部键盘，这可能会忽略按键。使用 KbStrokeWait(-3) 将检查所有连接的设备。
你的分布函数似乎要么没有收敛于一个解决方案，要么花了很长时间来确定一个解决方案，因为它似乎是随机生成值然后检查它是否足够所需的间隔。相反，我会从生成随机正常值的内置函数开始。例如，以下将从均值为 0.02 且方差为 0.126 的分布生成 5 个值。它没有实现检查所有生成的值是否在给定范围内，但是：randn(1, 5) * sqrt(0.126) + 0.02;
您在调用 DrawText 时缺少 window 指针。

可能还有其他问题，但解决这些问题会让您入门。

只执行了部分代码，不显示任何错误信息

Only a portion of the code is executed and no error message is displayed

matlab

gaussian

psychtoolbox