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41 lines
1.1 KiB
Cython
41 lines
1.1 KiB
Cython
# Copyright James Hensman and Alan Saul 2015
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import numpy as np
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cimport numpy as np
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from . import linalg
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def flat_to_triang(np.ndarray[double, ndim=2] flat, int M):
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"""take a matrix N x D and return a M X M x D array where
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N = M(M+1)/2
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the lower triangluar portion of the d'th slice of the result is filled by the d'th column of flat.
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"""
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cdef int N = flat.shape[0]
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cdef int D = flat.shape[1]
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cdef int count = 0
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cdef np.ndarray[double, ndim=3] ret = np.zeros((M, M, D))
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for d in range(D):
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count = 0
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for m in range(M):
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for mm in range(m+1):
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ret[m, mm, d] = flat[count,d]
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count += 1
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return ret
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def triang_to_flat(np.ndarray[double, ndim=3] L):
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cdef int M = L.shape[0]
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cdef int D = L.shape[2]
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cdef int N = M*(M+1)/2
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cdef int count = 0
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cdef np.ndarray[double, ndim=2] flat = np.empty((N, D))
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for d in range(D):
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count = 0
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for m in range(M):
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for mm in range(m+1):
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flat[count,d] = L[m, mm, d]
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count += 1
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return flat
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