Merge pull request #1839 from joschmitt/js/prec

Make `set_precision` reduce the element
Nemocas · Aug 27, 2024 · 735c97c · 735c97c
2 parents 1ca3c48 + b3bafa5
commit 735c97c
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Showing 30 changed files with 761 additions and 160 deletions.
diff --git a/src/flint/fmpq_abs_series.jl b/src/flint/fmpq_abs_series.jl
@@ -116,6 +116,13 @@ end
 
 characteristic(::QQAbsPowerSeriesRing) = 0
 
+function set_precision!(z::QQAbsPowerSeriesRingElem, k::Int)
+  k < 0 && throw(DomainError(k, "Precision must be non-negative"))
+  z = truncate!(z, k)
+  z.prec = k
+  return z
+end
+
 ###############################################################################
 #
 #   Similar
@@ -340,17 +347,20 @@ end
 #
 ###############################################################################
 
-function truncate(x::QQAbsPowerSeriesRingElem, prec::Int)
-  prec < 0 && throw(DomainError(prec, "Precision must be non-negative"))
-  if x.prec <= prec
+function truncate(x::QQAbsPowerSeriesRingElem, k::Int)
+  return truncate!(deepcopy(x), k)
+end
+
+function truncate!(x::QQAbsPowerSeriesRingElem, k::Int)
+  k < 0 && throw(DomainError(k, "Index must be non-negative"))
+  if precision(x) <= k
     return x
   end
-  z = parent(x)()
-  z.prec = prec
-  ccall((:fmpq_poly_set_trunc, libflint), Nothing,
-        (Ref{QQAbsPowerSeriesRingElem}, Ref{QQAbsPowerSeriesRingElem}, Int),
-        z, x, prec)
-  return z
+  ccall((:fmpq_poly_truncate, libflint), Nothing,
+        (Ref{QQAbsPowerSeriesRingElem}, Int),
+        x, k)
+  x.prec = k
+  return x
 end
 
 ###############################################################################

diff --git a/src/flint/fmpq_rel_series.jl b/src/flint/fmpq_rel_series.jl
@@ -109,6 +109,16 @@ end
 
 characteristic(::QQRelPowerSeriesRing) = 0
 
+function set_precision!(z::QQRelPowerSeriesRingElem, k::Int)
+  k < 0 && throw(DomainError(k, "Precision must be non-negative"))
+  z = truncate!(z, k)
+  z.prec = k
+  if is_zero(z)
+    z.val = k
+  end
+  return z
+end
+
 ###############################################################################
 #
 #   Similar
@@ -388,27 +398,25 @@ end
 #
 ###############################################################################
 
-function truncate(x::QQRelPowerSeriesRingElem, prec::Int)
-  prec < 0 && throw(DomainError(prec, "Index must be non-negative"))
-  xlen = pol_length(x)
-  xprec = precision(x)
-  xval = valuation(x)
-  if xprec + xval <= prec
+function truncate(x::QQRelPowerSeriesRingElem, k::Int)
+  return truncate!(deepcopy(x), k)
+end
+
+function truncate!(x::QQRelPowerSeriesRingElem, k::Int)
+  k < 0 && throw(DomainError(k, "Index must be non-negative"))
+  if precision(x) <= k
     return x
   end
-  z = parent(x)()
-  z.prec = prec
-  if prec <= xval
-    z = parent(x)()
-    z.val = prec
-    z.prec = prec
+  if k <= valuation(x)
+    x = zero!(x)
+    x.val = k
   else
-    z.val = xval
-    ccall((:fmpq_poly_set_trunc, libflint), Nothing,
-          (Ref{QQRelPowerSeriesRingElem}, Ref{QQRelPowerSeriesRingElem}, Int),
-          z, x, min(prec - xval, xlen))
+    ccall((:fmpq_poly_truncate, libflint), Nothing,
+          (Ref{QQRelPowerSeriesRingElem}, Int),
+          x, k - valuation(x))
   end
-  return z
+  x.prec = k
+  return x
 end
 
 ###############################################################################

diff --git a/src/flint/fmpz_abs_series.jl b/src/flint/fmpz_abs_series.jl
@@ -115,6 +115,13 @@ end
 
 characteristic(::ZZAbsPowerSeriesRing) = 0
 
+function set_precision!(z::ZZAbsPowerSeriesRingElem, k::Int)
+  k < 0 && throw(DomainError(k, "Precision must be non-negative"))
+  z = truncate!(z, k)
+  z.prec = k
+  return z
+end
+
 ###############################################################################
 #
 #   Similar
@@ -328,17 +335,20 @@ end
 #
 ###############################################################################
 
-function truncate(x::ZZAbsPowerSeriesRingElem, prec::Int)
-  prec < 0 && throw(DomainError(prec, "Index must be non-negative"))
-  if x.prec <= prec
+function truncate(x::ZZAbsPowerSeriesRingElem, k::Int)
+  return truncate!(deepcopy(x), k)
+end
+
+function truncate!(x::ZZAbsPowerSeriesRingElem, k::Int)
+  k < 0 && throw(DomainError(k, "Index must be non-negative"))
+  if precision(x) <= k
     return x
   end
-  z = parent(x)()
-  z.prec = prec
-  ccall((:fmpz_poly_set_trunc, libflint), Nothing,
-        (Ref{ZZAbsPowerSeriesRingElem}, Ref{ZZAbsPowerSeriesRingElem}, Int),
-        z, x, prec)
-  return z
+  ccall((:fmpz_poly_truncate, libflint), Nothing,
+        (Ref{ZZAbsPowerSeriesRingElem}, Int),
+        x, k)
+  x.prec = k
+  return x
 end
 
 ###############################################################################

diff --git a/src/flint/fmpz_mod_abs_series.jl b/src/flint/fmpz_mod_abs_series.jl
@@ -135,6 +135,13 @@ for (etype, rtype, ctype, mtype, brtype, flint_fn) in (
 
     characteristic(R::($rtype)) = characteristic(base_ring(R))
 
+    function set_precision!(z::($etype), k::Int)
+      k < 0 && throw(DomainError(k, "Precision must be non-negative"))
+      z = truncate!(z, k)
+      z.prec = k
+      return z
+    end
+
     ###############################################################################
     #
     #   Similar
@@ -345,18 +352,20 @@ for (etype, rtype, ctype, mtype, brtype, flint_fn) in (
     #
     ###############################################################################
 
-    function truncate(x::($etype), prec::Int)
-      prec < 0 && throw(DomainError(prec, "Index must be non-negative"))
-      if x.prec <= prec
+    function truncate(x::($etype), k::Int)
+      return truncate!(deepcopy(x), k)
+    end
+
+    function truncate!(x::($etype), k::Int)
+      k < 0 && throw(DomainError(k, "Index must be non-negative"))
+      if precision(x) <= k
         return x
       end
-      z = parent(x)()
-      z.prec = prec
-      ccall(($(flint_fn*"_set_trunc"), libflint), Nothing,
-            (Ref{($etype)}, Ref{($etype)}, Int,
-             Ref{($ctype)}),
-            z, x, prec, x.parent.base_ring.ninv)
-      return z
+      ccall(($(flint_fn*"_truncate"), libflint), Nothing,
+            (Ref{($etype)}, Int, Ref{($ctype)}),
+            x, k, x.parent.base_ring.ninv)
+      x.prec = k
+      return x
     end
 
     ###############################################################################

diff --git a/src/flint/fmpz_mod_rel_series.jl b/src/flint/fmpz_mod_rel_series.jl
@@ -124,6 +124,16 @@ for (etype, rtype, ctype, mtype, brtype, flint_fn) in (
 
     characteristic(R::($rtype)) = modulus(R)
 
+    function set_precision!(z::($etype), k::Int)
+      k < 0 && throw(DomainError(k, "Precision must be non-negative"))
+      z = truncate!(z, k)
+      z.prec = k
+      if is_zero(z)
+        z.val = k
+      end
+      return z
+    end
+
     ###############################################################################
     #
     #   Similar
@@ -399,28 +409,25 @@ for (etype, rtype, ctype, mtype, brtype, flint_fn) in (
     #
     ###############################################################################
 
-    function truncate(x::($etype), prec::Int)
-      prec < 0 && throw(DomainError(prec, "Index must be non-negative"))
-      xlen = pol_length(x)
-      xprec = precision(x)
-      xval = valuation(x)
-      if xprec + xval <= prec
+    function truncate(x::($etype), k::Int)
+      return truncate!(deepcopy(x), k)
+    end
+
+    function truncate!(x::($etype), k::Int)
+      k < 0 && throw(DomainError(k, "Index must be non-negative"))
+      if precision(x) <= k
         return x
       end
-      z = parent(x)()
-      z.prec = prec
-      if prec <= xval
-        z = parent(x)()
-        z.val = prec
-        z.prec = prec
+      if k <= valuation(x)
+        x = zero!(x)
+        x.val = k
       else
-        z.val = xval
-        ccall(($(flint_fn*"_set_trunc"), libflint), Nothing,
-              (Ref{($etype)}, Ref{($etype)}, Int,
-               Ref{($ctype)}),
-              z, x, min(prec - xval, xlen), x.parent.base_ring.ninv)
+        ccall(($(flint_fn*"_truncate"), libflint), Nothing,
+              (Ref{($etype)}, Int, Ref{$(ctype)}),
+              x, k - valuation(x), x.parent.base_ring.ninv)
       end
-      return z
+      x.prec = k
+      return x
     end
 
     ###############################################################################

diff --git a/src/flint/fmpz_rel_series.jl b/src/flint/fmpz_rel_series.jl
@@ -109,6 +109,16 @@ end
 
 characteristic(::ZZRelPowerSeriesRing) = 0
 
+function set_precision!(z::ZZRelPowerSeriesRingElem, k::Int)
+  k < 0 && throw(DomainError(k, "Precision must be non-negative"))
+  z = truncate!(z, k)
+  z.prec = k
+  if is_zero(z)
+    z.val = k
+  end
+  return z
+end
+
 ###############################################################################
 #
 #   Similar
@@ -357,27 +367,25 @@ end
 #
 ###############################################################################
 
-function truncate(x::ZZRelPowerSeriesRingElem, prec::Int)
-  prec < 0 && throw(DomainError(prec, "Index must be non-negative"))
-  xlen = pol_length(x)
-  xprec = precision(x)
-  xval = valuation(x)
-  if xprec + xval <= prec
+function truncate(x::ZZRelPowerSeriesRingElem, k::Int)
+  return truncate!(deepcopy(x), k)
+end
+
+function truncate!(x::ZZRelPowerSeriesRingElem, k::Int)
+  k < 0 && throw(DomainError(k, "Index must be non-negative"))
+  if precision(x) <= k
     return x
   end
-  z = parent(x)()
-  z.prec = prec
-  if prec <= xval
-    z = parent(x)()
-    z.val = prec
-    z.prec = prec
+  if k <= valuation(x)
+    x = zero!(x)
+    x.val = k
   else
-    z.val = xval
-    ccall((:fmpz_poly_set_trunc, libflint), Nothing,
-          (Ref{ZZRelPowerSeriesRingElem}, Ref{ZZRelPowerSeriesRingElem}, Int),
-          z, x, min(prec - xval, xlen))
+    ccall((:fmpz_poly_truncate, libflint), Nothing,
+          (Ref{ZZRelPowerSeriesRingElem}, Int),
+          x, k - valuation(x))
   end
-  return z
+  x.prec = k
+  return x
 end
 
 ###############################################################################

diff --git a/src/flint/fq_abs_series.jl b/src/flint/fq_abs_series.jl
@@ -128,6 +128,13 @@ for (etype, rtype, ctype, btype, flint_fn, flint_tail) in (
 
     characteristic(R::($rtype)) = characteristic(base_ring(R))
 
+    function set_precision!(z::($etype), k::Int)
+      k < 0 && throw(DomainError(k, "Precision must be non-negative"))
+      z = truncate!(z, k)
+      z.prec = k
+      return z
+    end
+
     ###############################################################################
     #
     #   Similar
@@ -305,17 +312,20 @@ for (etype, rtype, ctype, btype, flint_fn, flint_tail) in (
     #
     ###############################################################################
 
-    function truncate(x::($etype), prec::Int)
-      prec < 0 && throw(DomainError(prec, "Index must be non-negative"))
-      if x.prec <= prec
+    function truncate(x::($etype), k::Int)
+      return truncate!(deepcopy(x), k)
+    end
+
+    function truncate!(x::($etype), k::Int)
+      k < 0 && throw(DomainError(k, "Index must be non-negative"))
+      if precision(x) <= k
         return x
       end
-      z = parent(x)()
-      z.prec = prec
-      ccall(($(flint_fn*"_set_trunc"), libflint), Nothing,
-            (Ref{($etype)}, Ref{($etype)}, Int, Ref{($ctype)}),
-            z, x, prec, base_ring(x))
-      return z
+      ccall(($(flint_fn*"_truncate"), libflint), Nothing,
+            (Ref{($etype)}, Int, Ref{($ctype)}),
+            x, k, base_ring(x))
+      x.prec = k
+      return x
     end
 
     ###############################################################################