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moved warning after some examples
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‎src/sage/calculus/calculus.py

+35-33
Original file line numberDiff line numberDiff line change
@@ -435,39 +435,6 @@ def symbolic_sum(expression, v, a, b, algorithm='maxima'):
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Returns the symbolic sum `\sum_{v = a}^b expression` with respect
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to the variable `v` with endpoints `a` and `b`.
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.. WARNING::
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This function only works with symbolic expressions. To sum any
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other objects like list elements or function return values,
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please use python summation, see
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http://docs.python.org/2.7/library/functions.html#sum
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In particular, this does not work::
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sage: n = var('n')
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sage: list=[1,2,3,4,5]
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sage: sum(list[n],n,0,3)
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Traceback (most recent call last):
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...
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TypeError: unable to convert x (=n) to an integer
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Use python sum() instead::
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sage: sum(list[n] for n in range(4))
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10
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Also, only a limited number of functions are recognized in symbolic sums::
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sage: sum(valuation(n,2),n,1,5)
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Traceback (most recent call last):
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...
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AttributeError: 'sage.symbolic.expression.Expression' object has no attribute 'valuation'
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Again, use python sum()::
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sage: sum(valuation(n+1,2) for n in range(5))
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3
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INPUT:
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- ``expression`` - a symbolic expression
@@ -501,6 +468,41 @@ def symbolic_sum(expression, v, a, b, algorithm='maxima'):
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sage: symbolic_sum(1/k^5, k, 1, oo)
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zeta(5)
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.. WARNING::
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This function only works with symbolic expressions. To sum any
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other objects like list elements or function return values,
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please use python summation, see
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http://docs.python.org/library/functions.html#sum
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In particular, this does not work::
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sage: n = var('n')
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sage: list=[1,2,3,4,5]
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sage: sum(list[n],n,0,3)
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Traceback (most recent call last):
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...
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TypeError: unable to convert x (=n) to an integer
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Use python ``sum()`` instead::
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sage: sum(list[n] for n in range(4))
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10
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Also, only a limited number of functions are recognized in symbolic sums::
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sage: sum(valuation(n,2),n,1,5)
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Traceback (most recent call last):
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...
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AttributeError: 'sage.symbolic.expression.Expression' object has no attribute 'valuation'
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Again, use python ``sum()``::
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sage: sum(valuation(n+1,2) for n in range(5))
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3
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(now back to the Sage ``sum`` examples)
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504506
A well known binomial identity::
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sage: symbolic_sum(binomial(n,k), k, 0, n)

‎src/sage/misc/functional.py

+35-33
Original file line numberDiff line numberDiff line change
@@ -542,39 +542,6 @@ def symbolic_sum(expression, *args, **kwds):
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Returns the symbolic sum `\sum_{v = a}^b expression` with respect
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to the variable `v` with endpoints `a` and `b`.
544544
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.. WARNING::
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This function only works with symbolic expressions. To sum any
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other objects like list elements or function return values,
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please use python summation, see
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http://docs.python.org/2.7/library/functions.html#sum
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In particular, this does not work::
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sage: n = var('n')
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sage: list=[1,2,3,4,5]
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sage: sum(list[n],n,0,3)
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Traceback (most recent call last):
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...
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TypeError: unable to convert x (=n) to an integer
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Use python sum() instead::
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sage: sum(list[n] for n in range(4))
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10
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Also, only a limited number of functions are recognized in symbolic sums::
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sage: sum(valuation(n,2),n,1,5)
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Traceback (most recent call last):
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...
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AttributeError: 'sage.symbolic.expression.Expression' object has no attribute 'valuation'
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Again, use python sum()::
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sage: sum(valuation(n+1,2) for n in range(5))
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3
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578545
INPUT:
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- ``expression`` - a symbolic expression
@@ -606,6 +573,41 @@ def symbolic_sum(expression, *args, **kwds):
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sage: sum(1/k^5, k, 1, oo)
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zeta(5)
608575
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.. WARNING::
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This function only works with symbolic expressions. To sum any
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other objects like list elements or function return values,
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please use python summation, see
581+
http://docs.python.org/library/functions.html#sum
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In particular, this does not work::
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sage: n = var('n')
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sage: list=[1,2,3,4,5]
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sage: sum(list[n],n,0,3)
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Traceback (most recent call last):
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...
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TypeError: unable to convert x (=n) to an integer
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Use python ``sum()`` instead::
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sage: sum(list[n] for n in range(4))
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10
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Also, only a limited number of functions are recognized in symbolic sums::
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sage: sum(valuation(n,2),n,1,5)
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Traceback (most recent call last):
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...
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AttributeError: 'sage.symbolic.expression.Expression' object has no attribute 'valuation'
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Again, use python ``sum()``::
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sage: sum(valuation(n+1,2) for n in range(5))
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3
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(now back to the Sage ``sum`` examples)
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A well known binomial identity::
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sage: sum(binomial(n,k), k, 0, n)

‎src/sage/symbolic/expression.pyx

+35-33
Original file line numberDiff line numberDiff line change
@@ -9752,39 +9752,6 @@ cdef class Expression(CommutativeRingElement):
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with respect to the variable `v` with endpoints
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`a` and `b`.
97549754
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.. WARNING::
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This function only works with symbolic expressions. To sum any
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other objects like list elements or function return values,
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please use python summation, see
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http://docs.python.org/2.7/library/functions.html#sum
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9762-
In particular, this does not work::
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sage: n = var('n')
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sage: list=[1,2,3,4,5]
9766-
sage: sum(list[n],n,0,3)
9767-
Traceback (most recent call last):
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...
9769-
TypeError: unable to convert x (=n) to an integer
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9771-
Use python sum() instead::
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9773-
sage: sum(list[n] for n in range(4))
9774-
10
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9776-
Also, only a limited number of functions are recognized in symbolic sums::
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9778-
sage: sum(valuation(n,2),n,1,5)
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Traceback (most recent call last):
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...
9781-
AttributeError: 'sage.symbolic.expression.Expression' object has no attribute 'valuation'
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Again, use python sum()::
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sage: sum(valuation(n+1,2) for n in range(5))
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3
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97889755
INPUT:
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97909757
- ``v`` - a variable or variable name
@@ -9820,6 +9787,41 @@ cdef class Expression(CommutativeRingElement):
98209787
sage: (1/k^5).sum(k, 1, oo)
98219788
zeta(5)
98229789
9790+
.. WARNING::
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This function only works with symbolic expressions. To sum any
9793+
other objects like list elements or function return values,
9794+
please use python summation, see
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http://docs.python.org/library/functions.html#sum
9796+
9797+
In particular, this does not work::
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sage: n = var('n')
9800+
sage: list=[1,2,3,4,5]
9801+
sage: sum(list[n],n,0,3)
9802+
Traceback (most recent call last):
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...
9804+
TypeError: unable to convert x (=n) to an integer
9805+
9806+
Use python ``sum()`` instead::
9807+
9808+
sage: sum(list[n] for n in range(4))
9809+
10
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9811+
Also, only a limited number of functions are recognized in symbolic sums::
9812+
9813+
sage: sum(valuation(n,2),n,1,5)
9814+
Traceback (most recent call last):
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...
9816+
AttributeError: 'sage.symbolic.expression.Expression' object has no attribute 'valuation'
9817+
9818+
Again, use python ``sum()``::
9819+
9820+
sage: sum(valuation(n+1,2) for n in range(5))
9821+
3
9822+
9823+
(now back to the Sage ``sum`` examples)
9824+
98239825
A well known binomial identity::
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98259827
sage: assume(n>=0)

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