Matrix is close to singular or badly scaled. Results may be inaccurate. RCOND = 2.947558e-19. what dose it mean

Matrix is close to singular or badly scaled. Results may be inaccurate. RCOND = 2.947558e-19.

Answer 1

[Walter Roberson]

https://www.mathworks.com/help/matlab/ref/rcond.html

When the reciprocal condition number is very small, then the condition number is large.

"The condition number takes on values between 1 and infinity, inclusive, and can be viewed as a factor by which errors in solving linear systems with this matrix as coefficient matrix could be magnified. " (citation: https://stat.ethz.ch/R-manual/R-devel/library/Matrix/html/rcond.html )

rcond is a lower-accuracy method that computes 1/cond()

With your matrix, a single bit different in your coefficient would be multiplied by about 1/2.947558e-19 = 3.3E+18 during calculations, which is probably going to make the calculations useless.

Your matrix might be singular, or it might just be very badly scaled; check rank() of the matrix.

[prabin kumar]

Thanks Walter