If statement with multiple conditions

clear all; clc; close all

Tp=[4 7 11 16];
u= [0.188 0.368 0.628 0.997]; 
u10= [5.5 9.7 15 21];

ni_a=1.326*10^(-5);
sigma_p=2.*pi.*Tp.^(-1); 
w2=((u.^2)./(ni_a.*sigma_p)).^(1.5);

r0=30:10:500;

SSGF = zeros(numel(Tp),numel(r0));
for Tp_Idx=1:length(Tp)
    for r0_Idx=1:length(r0)
        if Tp==4
            if 30<=r0<75
                SSGF=(7.84.*10.^(-3)).*r0.^(-1).*r0;
            elseif 75<=r0<200
                SSGF=4.41.*10.*(r0.^(-3)).*r0;
            else 
                SSGF=(1.41.*10.^(13)).*r0.^(-8).*r0;
            end
        elseif Tp==7
            if 30<=r0<75
                SSGF=(7.84.*10.^(-3)).*r0.^(-1).*r0;
            elseif 75<=r0<200
                SSGF=4.41.*10.*(r0.^(-3)).*r0;
            else 
                SSGF=(1.41.*10.^(13)).*r0.^(-8).*r0;
            end
         elseif Tp==11
            if 30<=r0<75
                SSGF=(7.84.*10.^(-3)).*r0.^(-1).*r0;
            elseif 75<=r0<200
                SSGF=4.41.*10.*(r0.^(-3)).*r0;
            else 
                SSGF=(1.41.*10.^(13)).*r0.^(-8).*r0;
            end
        else
             if 30<=r0<75
                SSGF=(7.84.*10.^(-3)).*r0.^(-1).*r0;
            elseif 75<=r0<200
                SSGF=4.41.*10.*(r0.^(-3)).*r0;
            else 
                SSGF=(1.41.*10.^(13)).*r0.^(-8).*r0;
            end
        end
    end
end

Above is my code and my problem is that I am not able to make a matrix with 4 columns and 48 lines (SSGF). A piece of the table that was supposed to come out is in the image below.

Thanks in advance

Answer 1

[Walter Roberson]

if 30<=r0<75

means the same as

if ((30<=r0)<75)

The first part, 30<=r0, returns 0 (false) or 1 (true). Then you compare that 0 or 1 to 75.

You need to use &&

if 30 <= r0 && r0 < 75

[Jacqueline Rigatto]

Thank you very much Walter Roberson, it helped a lot

Answer 2

[Alan Stevens]

Don't forget the indices:

 if Tp(Tp_Idx)==4
            if 30<=r0(r0_Idx)<75
                SSGF(Tp_Idx,r0_idx)=(7.84.*10.^(-3)).*r0(ro_Idx).^(-1).*r0(r0_Idx);
            ...etc.

[Jacqueline Rigatto]

Thank you very much Alan Stevens, it helped a lot