How can I repeatedly put a function result into itself, and get a matrix of the results?

조회 수: 6 (최근 30일)
I want to take the output of a function and put it back into the function to get my next output, then get a matrix of all the results. For example, if my function was b=3*a+1, I would want to get the matrix [4, 13, 40, 121...] etc, but a very large size, eg. 500 numbers.
Here's how I'm currently doing it. I have the function:
function [ y ] = test( x )
%UNTITLED2 Summary of this function goes here
% Detailed explanation goes here
assignin('base', 'B', evalin('base', 'B')+1)
The purpose of the assignin bit is to increase B (a variable in my main workspace) by 1 every time I use the function.
I start by setting B as 0. Then in my command window I do:
This sets M as 4.
Then I do:
This makes M a 1x2 matrix [4, 13].
I have to keep repeating this last command to get more values in matrix M.
Is there a way I could get, let's say, 500 values of M all at once, giving me a 1x500 matrix in one go?
P.S. 3X+1 is just an example - the equation I'm actually using is a bit more complicated, so finding a general equation for the nth term won't help.
I'm on 2016a

답변 (1개)

Thorsten 2017년 4월 19일
편집: Thorsten 2017년 4월 19일
N = 500;
Y = zeros(1, N); % preallocate for speed
Y(1) = myfun(1);
for i = 2:N
Y(i) = myfun(Y(i-1);
with myfun.m defined as
function y = myfun(x) % use a name for the function that is not a Matlab command
y = 3*x+1;


Help CenterFile Exchange에서 Loops and Conditional Statements에 대해 자세히 알아보기


아직 태그를 입력하지 않았습니다.


Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by