rounding issues in matlab, need to force values to 0

How do force matlab to set specfic function values at 0 instead of 1.34e-18 or something small. the if and else statements dont work and the treshold code (X(X<treshold))=0; doesnt work as that defaults some of my Xn (y1.....y4) values to be null/0 and phase becomes 0.

%y2 = 100e-3*1/5*sinc(n*1/5);

%y3 = 100e-3*1/7*sinc(n*1/7);

%y4 = 100e-3*1/2*( sinc (n*1/2) ).^2;

n = -15:1:15;

y1 = 100e-3*1/2*sinc(n*1/2);

if abs(y1)< 1e-6

y1=0;

end

figure(1)

stem(n,abs(y1),'r','LineWidth',1.4)

ylabel('Xn (Volts)'); xlabel('n'); title(' Pulse Amplitude Spectrum [DC=1/2]'); grid on

figure(2)

stem(n,angle(y1)*180/pi,'b','LineWidth',1.4)

ylabel('Phase (Degrees)'); xlabel('n'); title('Pulse Phase Spectrum [DC=1/2]'); grid on

%{

figure(3)

stem(n,abs(y2),'r','LineWidth',1.4)

ylabel('Xn (Volts)'); xlabel('n'); title('Pulse Amplitude Spectrum [DC=1/5]'); grid on

figure(4)

stem(n,angle(y2)*180/pi,'b','LineWidth',1.4)

ylabel('Phase (Degrees)'); xlabel('n'); title(' Pulse Phase Spectrum [DC=1/5]'); grid on

i dont want to recreate my code and use loops, any ideas how to force those super small values to 0, so that they dont affect my phase diagram

[Benjamin Thompson]

You can use an index vector with ones in the spots that you want to replace with zero, similar to:

>> X

X =

1.0e-06 *

0.6555

0.1712

0.7060

0.0318

0.2769

>> I = (abs(X) < 1e-7)

I =

5×1 logical array

0

0

0

1

0

>> X(I) = 0

X =

1.0e-06 *

0.6555

0.1712

0.7060

0

0.2769

Answer 1

[James Tursa]

Instead of

if abs(y1)< 1e-6
    y1=0;
end

try

y1(abs(y1)<1e-6) = 0;

Answer 2

[Benjamin Thompson]

You can use an index vector with ones in the spots that you want to replace with zero, similar to:

>> X

X =

1.0e-06 *

0.6555

0.1712

0.7060

0.0318

0.2769

>> I = (abs(X) < 1e-7)

I =

5×1 logical array

0

0

0

1

0

>> X(I) = 0

X =

1.0e-06 *

0.6555

0.1712

0.7060

0

0.2769