Merge pull request #307 from isuruf/linsolve

Linsolve

Author: isuruf

symengine/__init__.py

@@ -12,6 +12,7 @@
     LessThan, StrictGreaterThan, StrictLessThan, Eq, Ne, Ge, Le,
     Gt, Lt, And, Or, Not, Nand, Nor, Xor, Xnor, perfect_power, integer_nthroot,
     isprime, sqrt_mod, Expr, cse, count_ops, ccode, Piecewise, Contains, Interval, FiniteSet,
+    EmptySet, linsolve,
     FunctionSymbol as AppliedUndef,
     golden_ratio as GoldenRatio,
     catalan as Catalan,

symengine/lib/symengine.pxd

@@ -171,6 +171,7 @@ cdef extern from "<symengine/basic.h>" namespace "SymEngine":
         void insert(iterator, iterator) except +
 
     ctypedef vector[rcp_const_basic] vec_basic "SymEngine::vec_basic"
+    ctypedef vector[RCP[Symbol]] vec_sym "SymEngine::vec_sym"
     ctypedef vector[RCP[Integer]] vec_integer "SymEngine::vec_integer"
     ctypedef map[RCP[Integer], unsigned] map_integer_uint "SymEngine::map_integer_uint"
     cdef struct RCPIntegerKeyLess
@@ -1047,6 +1048,7 @@ cdef extern from "<symengine/sets.h>" namespace "SymEngine":
 cdef extern from "<symengine/solve.h>" namespace "SymEngine":
     cdef RCP[const Set] solve(rcp_const_basic &f, RCP[const Symbol] &sym) nogil except +
     cdef RCP[const Set] solve(rcp_const_basic &f, RCP[const Symbol] &sym, RCP[const Set] &domain) nogil except +
+    cdef vec_basic linsolve(const vec_basic &eqs, const vec_sym &syms) nogil except +
 
 cdef extern from "<symengine/printers.h>" namespace "SymEngine":
     string ccode(const Basic &x) nogil except +

symengine/lib/symengine_wrapper.pyx

@@ -2068,11 +2068,7 @@ class Add(AssocOp):
     identity = 0
 
     def __new__(cls, *args, **kwargs):
-        cdef symengine.vec_basic v_
-        cdef Basic e
-        for e_ in args:
-            e = _sympify(e_)
-            v_.push_back(e.thisptr)
+        cdef symengine.vec_basic v_ = iter_to_vec_basic(args)
         return c2py(symengine.add(v_))
 
     @classmethod
@@ -2123,11 +2119,7 @@ class Mul(AssocOp):
     identity = 1
 
     def __new__(cls, *args, **kwargs):
-        cdef symengine.vec_basic v_
-        cdef Basic e
-        for e_ in args:
-            e = _sympify(e_)
-            v_.push_back(e.thisptr)
+        cdef symengine.vec_basic v_ = iter_to_vec_basic(args)
         return c2py(symengine.mul(v_))
 
     @classmethod
@@ -2296,11 +2288,7 @@ class KroneckerDelta(Function):
 
 class LeviCivita(Function):
     def __new__(cls, *args):
-        cdef symengine.vec_basic v
-        cdef Basic e_
-        for e in args:
-            e_ = sympify(e)
-            v.push_back(e_.thisptr)
+        cdef symengine.vec_basic v = iter_to_vec_basic(args)
         return c2py(symengine.levi_civita(v))
 
     def _sympy_(self):
@@ -2710,11 +2698,7 @@ class PyFunction(FunctionSymbol):
     def __init__(Basic self, pyfunction = None, args = None, pyfunction_class=None, module=None):
         if pyfunction is None:
             return
-        cdef symengine.vec_basic v
-        cdef Basic arg_
-        for arg in args:
-            arg_ = sympify(arg)
-            v.push_back(arg_.thisptr)
+        cdef symengine.vec_basic v = iter_to_vec_basic(args)
         cdef PyFunctionClass _pyfunction_class = get_function_class(pyfunction_class, module)
         cdef PyObject* _pyfunction = <PyObject*>pyfunction
         Py_XINCREF(_pyfunction)
@@ -3785,42 +3769,53 @@ cdef class ImmutableDenseMatrix(DenseMatrixBase):
 
 ImmutableMatrix = ImmutableDenseMatrix
 
+
 cdef matrix_to_vec(DenseMatrixBase d, symengine.vec_basic& v):
     cdef Basic e_
     for i in range(d.nrows()):
         for j in range(d.ncols()):
             e_ = d._get(i, j)
             v.push_back(e_.thisptr)
 
+
 def eye(n):
     cdef DenseMatrixBase d = DenseMatrix(n, n)
     symengine.eye(deref(symengine.static_cast_DenseMatrix(d.thisptr)), 0)
     return d
 
-def diag(*values):
-    cdef DenseMatrixBase d = DenseMatrix(len(values), len(values))
-    cdef symengine.vec_basic V
+
+cdef symengine.vec_basic iter_to_vec_basic(iter):
     cdef Basic B
-    for b in values:
+    cdef symengine.vec_basic V
+    for b in iter:
         B = sympify(b)
         V.push_back(B.thisptr)
+    return V
+
+
+def diag(*values):
+    cdef DenseMatrixBase d = DenseMatrix(len(values), len(values))
+    cdef symengine.vec_basic V = iter_to_vec_basic(values)
     symengine.diag(deref(symengine.static_cast_DenseMatrix(d.thisptr)), V, 0)
     return d
 
+
 def ones(r, c = None):
     if c is None:
         c = r
     cdef DenseMatrixBase d = DenseMatrix(r, c)
     symengine.ones(deref(symengine.static_cast_DenseMatrix(d.thisptr)))
     return d
 
+
 def zeros(r, c = None):
     if c is None:
         c = r
     cdef DenseMatrixBase d = DenseMatrix(r, c)
     symengine.zeros(deref(symengine.static_cast_DenseMatrix(d.thisptr)))
     return d
 
+
 cdef class Sieve:
     @staticmethod
     def generate_primes(n):
@@ -3831,6 +3826,7 @@ cdef class Sieve:
             s.append(primes[i])
         return s
 
+
 cdef class Sieve_iterator:
     cdef symengine.sieve_iterator *thisptr
     cdef unsigned limit
@@ -5000,6 +4996,25 @@ def solve(f, sym, domain=None):
     return c2py(<rcp_const_basic>(symengine.solve(f_.thisptr, x, d)))
 
 
+def linsolve(eqs, syms):
+    """
+    Solve a set of linear equations given as an iterable `eqs`
+    which are linear w.r.t the symbols given as an iterable `syms`
+    """
+    cdef symengine.vec_basic eqs_ = iter_to_vec_basic(eqs)
+    cdef symengine.vec_sym syms_
+    cdef RCP[const symengine.Symbol] sym_
+    cdef Symbol B
+    for sym in syms:
+        B = sympify(sym)
+        sym_ = symengine.rcp_static_cast_Symbol(B.thisptr)
+        syms_.push_back(sym_)
+    if syms_.size() != eqs_.size():
+        raise RuntimeError("Number of equations and symbols do not match")
+    cdef symengine.vec_basic ret = symengine.linsolve(eqs_, syms_)
+    return vec_basic_to_tuple(ret)
+
+
 def cse(exprs):
     cdef symengine.vec_basic vec
     cdef symengine.vec_pair replacements

symengine/tests/test_solve.py

@@ -1,17 +1,25 @@
 from symengine.utilities import raises
-from symengine.lib.symengine_wrapper import (Interval, EmptySet, FiniteSet,
-	I, oo, solve, Eq, Symbol)
+from symengine import (Interval, EmptySet, FiniteSet, I, oo, Eq, Symbol,
+    linsolve)
+from symengine.lib.symengine_wrapper import solve
 
 def test_solve():
-	x = Symbol("x")
-	reals = Interval(-oo, oo)
+    x = Symbol("x")
+    reals = Interval(-oo, oo)
 
-	assert solve(1, x, reals) == EmptySet()
-	assert solve(0, x, reals) == reals
-	assert solve(x + 3, x, reals) == FiniteSet(-3)
-	assert solve(x + 3, x, Interval(0, oo)) == EmptySet()
-	assert solve(x, x, reals) == FiniteSet(0)
-	assert solve(x**2 + 1, x) == FiniteSet(-I, I)
-	assert solve(x**2 - 2*x + 1, x) == FiniteSet(1)
-	assert solve(Eq(x**3 + 3*x**2 + 3*x, -1), x, reals) == FiniteSet(-1)
-	assert solve(x**3 - x, x) == FiniteSet(0, 1, -1)
+    assert solve(1, x, reals) == EmptySet()
+    assert solve(0, x, reals) == reals
+    assert solve(x + 3, x, reals) == FiniteSet(-3)
+    assert solve(x + 3, x, Interval(0, oo)) == EmptySet()
+    assert solve(x, x, reals) == FiniteSet(0)
+    assert solve(x**2 + 1, x) == FiniteSet(-I, I)
+    assert solve(x**2 - 2*x + 1, x) == FiniteSet(1)
+    assert solve(Eq(x**3 + 3*x**2 + 3*x, -1), x, reals) == FiniteSet(-1)
+    assert solve(x**3 - x, x) == FiniteSet(0, 1, -1)
+
+def test_linsolve():
+    x = Symbol("x")
+    y = Symbol("y")
+    assert linsolve([x - 2], [x]) == (2,)
+    assert linsolve([x - 2, y - 3], [x, y]) == (2, 3)
+    assert linsolve([x + y - 3, x + 2*y - 4], [x, y]) == (2, 1)

symengine_version.txt

@@ -1 +1 @@
-v0.5.0
+fc05f8d55915c2de956e7797d764eb1116b61711