Both seem to be correct. Only the singular values are uniquely determined in an SVD, and only if they are ordered the same way. U and V are related, but not uniquely determined.
Note that with Math.NET Numerics, VT is already transposed (hence the T suffix), so H = UWVT. Once you transpose VT back to get V, the only difference between the two solutions is the negation of the middle column of both U and VT.
See How unique (on non-unique) are U and V in Singular Value Decomposition (SVD)? for some details on why this is allowed.
Thanks,
Christoph
Note that with Math.NET Numerics, VT is already transposed (hence the T suffix), so H = UWVT. Once you transpose VT back to get V, the only difference between the two solutions is the negation of the middle column of both U and VT.
See How unique (on non-unique) are U and V in Singular Value Decomposition (SVD)? for some details on why this is allowed.
Thanks,
Christoph