pdf and unifpdf functions not working

Question

Afeef Akhtar 2022-4-6

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1690210-pdf-and-unifpdf-functions-not-working

回答： Prahlad Gowtham Katte 2022-4-14

I am trying to get the Primary Distribution Function and have been using pdf functions to get them. They were working just fine last week but for some reason, they're not this time. I have even tried to use help for pdf and unifpdf and Matlab is telling me that they're undocumented builtin functions. In my code, the errors I am recieving are in lines 38 and 40. I am not sure if its because of an update or not. Would anyone have any solutions to this?

Here is my matlab code:

close all
clear all
x = randn(1,10000);
y = randn(1,10000)+1;
%x_cdf_graph = [0:0.1:8];
mu_x = mean(x);
var_x = var(x);
std_x = sqrt(var_x);
sigma_x = mean(x.^2)-mu_x^2
theta_x = var_x/mu_x;
k_x = mu_x/theta_x;
mu_y = mean(y);
var_y = var(y);
std_y = sqrt(var_y);
sigma_y = mean(y.^2)-mu_y^2
theta_y = var_y/mu_y;
k_x = mu_y/theta_y;
cov_x_y = cov(x,y);
E_xy = mean(x.*y)
E_w_x = mu_x/max(x);
Var_w_x = var_x/(max(x)^2);
autocorr_x = xcorr(x);
pow_x = fft(autocorr_x);
autocorr_y = xcorr(y);
pow_y = fft(autocorr_y);
row_xy = (E_xy - mu_x*mu_y)/(std_x*std_y)
r = xcorr(x, y);
z = 0:0.1:1;
pdf_x = pdf('Normal',[0:0.1:1], 0, 1)
pdf_y = unifpdf([0:0.1:1], 0, 1)
nbins_x = 25;
hist_x = histogram(x)
hNormalized_x = hist_x.Values / sum(hist_x.Values);
cdf_x = cumsum(hNormalized_x);
nbins_y = 25;
hist_y = histogram(y)
hNormalized_y = hist_y.Values / sum(hist_y.Values);
cdf_y = cumsum(hNormalized_y);
lin_est = row_xy*(std_y/std_x)*(x - mu_x) + mu_y
%X = [histogram(x)]
% hist_x = histogram(x);
% grid on;
% Figures 1 and 2 are histogram and CDF of x[n]
figure(1)
plot([0:0.1:1],pdf_x*500);
hold on
histogram(x);
figure(2)
plot(cdf_x);
% Figures 3 and 4 are histogram and CDF of y[n]
figure(3)
plot([0:0.1:1],pdf_y*500);
hold on
histogram(y);
figure(4)
plot(cdf_y);
% Figure 5 is the linear estimation x[n] and y[n]
figure(5)
plot(x,lin_est, x(1:500), y(1:500), '.');
% Figures 6 and 7 are the autocorrelation of x[n] and y[n]
figure(6)
plot(autocorr_x);
figure(7)
plot(autocorr_y);
% Figures 8 and 9 are power spectrums of x[n] and y[n]
figure(8)
plot(abs(pow_x));
figure(9)
plot(abs(pow_y));
% Joint pdf for x and y
figure(10)
hist3([x;y]');
% Figure 11 Joint cdf for x and y
mu = [0 1];
Sigma = [1 0; 0 1];
[A1,A2] = meshgrid(linspace(-10,10,25)',linspace(-10,10,25)');
A = [A1(:) A2(:)];
p = mvncdf(A,mu,Sigma);
Z = reshape(p,25,25);
figure(11)
surf(A1,A2,Z)

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Answer 1

Prahlad Gowtham Katte 2022-4-14

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链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1690210-pdf-and-unifpdf-functions-not-working#answer_942550

Hello Afeef

As per my understanding of your query there is something wrong with pdf and unifpdf functions. The code snippet you’ve shared seems to be working in my end. Please make sure that you have not named any script that you wrote as pdf.m or unifpdf.m.

Here is the link of documentation of those functions.

Continuous uniform probability density function - MATLAB unifpdf (mathworks.com)

Probability density function - MATLAB pdf (mathworks.com)

Hope it helps!