CODEWITHSUNDEEP
mathscilab
IsaacNuketon
IsaacNuketon

Reputation: 55

Scilab: "inconsistent multiplication" error message

I want to plot a curve with parametrisation x=... , y=... and z=... (see below). I keep getting error messages, mostly 'inconsistent multiplication'. Here is my code:

t = linspace(0,4*%pi)
x = (4+sin(63*t))*cos(3*t)
y = (4+sin(63*t))*sin(3*t)
z = cos(3*t)
param3d(x,y,z)

Could someone explain why I'm getting this error message or how my code should be corrected? I also tried to define x, y and z as functions.

Upvotes: 1

Views: 3578

Answers (1)

user3717023
user3717023

Reputation:

From the documentation of * operator:

Element-wise multiplication is denoted x.*y. If x or y is scalar (1x1 matrix) .* is the same as *.

So, in your case the formulas should be written as (4+sin(63*t)).*cos(3*t) because you want to multiply two arrays element-wise. Without the dot, the asterisk means matrix multiplication, and that fails because of mismatching size.

Examples: 

[1, 2] .* [3, 4] // returns [3, 8]
[1, 2] * [3, 4]  // error; one can't multiply a 1-by-2 matrix by another 1-by-2 matrix

One can also write 3.*t but here . is redundant since there is only one way to multiply a vector by a scalar.

Upvotes: 1

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