# how do you create a pascal matrix in matlab without the built in function?

I have been given the equation Pij = (i + j - 2)!/(i - 1)!(j - 1)! and I need to write a program that will create an n x n symmetric pascal matrix (that will prompt the user for n) without using matlabs build-in function.

Thanks

Relevance
• 9 years ago

Well the conventional way is to do it with while or for loops, however since matlab works so quick with matrices and vectors I decided to show you another approach. Treat i and j as matrices, and perform matrix operations on them. The variable 'i' will be a matrix of all the row numbers, and the variable 'j' will be the column numbers. The factorial function will perform the element by element factorial, so its a pretty simple problem. The program is below.

%Matlab Code:

%Prompt user for matrix size 'n'

n = input('Enter size of pascal matrix. \n');

%Initialize vector from 1 to n. Use to compute i,j

a = 1:n;

%Create j (The column numbers)

j = ones(n,1)*a;

%Flip j to create i (The row numbers)

i = j';

%Calculate Pij = (i + j - 2)!/(i - 1)!(j - 1)!

p = factorial(i + j - 2)./(factorial(i - 1).*factorial(j - 1));

%Echo p

p

• Anonymous
5 years ago

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• 5 years ago

write the following program in the script file:

clear all

clc

n=input( please entre the size of pascal matrix );

for i=1:n

for j=1:n

P(i,j) = factorial(i+j-2) / (factorial(i-1) * factorial(j-1));

end

end

P

run the file and you are there :) good luck