matrix¶
The matrix module defines an abstract Matrix
object and several
implementations. Matrix objects support basic addition and subtraction
operations and provide a consistent insterface for solving linear systems.
Matrices can be converted into other forms suitable for external processing via
the export
method.
-
class
nutils.matrix.
Backend
¶ Bases:
object
backend base class
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assemble
(self, data, index, shape)¶ Assemble a (sparse) tensor based on index-value pairs.
Note
This function is abstract.
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__weakref__
¶ list of weak references to the object (if defined)
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-
class
nutils.matrix.
Matrix
(shape)¶ Bases:
object
matrix base class
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__add__
(self, other)¶ add two matrices
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__mul__
(self, other)¶ multiply matrix with a scalar
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__neg__
(self, other)¶ negate matrix
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T
¶ transpose matrix
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rowsupp
(self, tol=0)¶ return row indices with nonzero/non-small entries
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solve
(self, rhs=None, *, lhs0=None, constrain=None, rconstrain=None, **solverargs)¶ Solve system given right hand side vector and/or constraints.
Parameters: - rhs (
float
vector orNone
) – Right hand side vector. None implies all zeros. - lhs0 (class:float vector or
None
) – Initial values. None implies all zeros. - constrain (
float
orbool
array, orNone
) – Column constraints. For float values, a number signifies a constraint, NaN signifies a free dof. For boolean, a True value signifies a constraint to the value in lhs0, a False value signifies a free dof. None implies no constraints. - rconstrain (
bool
array orNone
) – Row constrains. A True value signifies a constrains, a False value a free dof. None implies that the constraints follow those defined in constrain (by implication the matrix must be square).
Returns: Left hand side vector.
Return type: - rhs (
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submatrix
(self, rows, cols)¶ Create submatrix from selected rows, columns.
Parameters: Returns: Matrix instance of reduced dimensions
Return type:
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export
(self, form)¶ Export matrix data to any of supported forms.
Parameters: form ( str
) –- “dense” : return matrix as a single dense array
- ”csr” : return matrix as 3-tuple of (data, indices, indptr)
- ”coo” : return matrix as 2-tuple of (data, (row, col))
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__weakref__
¶ list of weak references to the object (if defined)
-
-
nutils.matrix.
preparesolvearguments
(wrapped)¶ Make rhs optional, add lhs0, constrain, rconstrain arguments.
See Matrix.solve.
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class
nutils.matrix.
Numpy
¶ Bases:
nutils.matrix.Backend
matrix backend based on numpy array
-
class
nutils.matrix.
NumpyMatrix
(core)¶ Bases:
nutils.matrix.Matrix
matrix based on numpy array
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class
nutils.matrix.
Scipy
¶ Bases:
nutils.matrix.Backend
matrix backend based on scipy’s sparse matrices
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class
nutils.matrix.
ScipyMatrix
(core)¶ Bases:
nutils.matrix.Matrix
matrix based on any of scipy’s sparse matrices