RANK ERROR: Difference between revisions
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A RANK ERROR is an [[error message]] which indicates that an array had an incorrect [[rank]] for the way it was used. For example, in most APLs, [[Iota]] only accepts a [[vector]] or [[scalar]], so giving it a higher-rank array results in a RANK ERROR: | A RANK ERROR is an [[error message]] which indicates that an array had an incorrect [[rank]] for the way it was used. For example, in most APLs, [[Iota]] only accepts a [[vector]] or [[scalar]], so giving it a higher-rank array results in a RANK ERROR: | ||
< | <source=apl> | ||
⍳2 3⍴⍳6 | ⍳2 3⍴⍳6 | ||
RANK ERROR | RANK ERROR | ||
⍳2 3⍴⍳6 | ⍳2 3⍴⍳6 | ||
∧ | ∧ | ||
</ | </source> | ||
A RANK ERROR can be caused when arguments do not [[Conformability|conform]] because they have differing ranks: | A RANK ERROR can be caused when arguments do not [[Conformability|conform]] because they have differing ranks: | ||
< | <source=apl> | ||
(2 3⍴2) + ⍳6 | (2 3⍴2) + ⍳6 | ||
RANK ERROR: Mismatched left and right argument ranks | RANK ERROR: Mismatched left and right argument ranks | ||
(2 3⍴2)+⍳6 | (2 3⍴2)+⍳6 | ||
∧ | ∧ | ||
</ | </source> | ||
It may also be caused when an array's rank is too small for a function. [[Windowed Reduction]] is not defined on scalars: | It may also be caused when an array's rank is too small for a function. [[Windowed Reduction]] is not defined on scalars: | ||
< | <source=apl> | ||
2 +/ 0.5 | 2 +/ 0.5 | ||
RANK ERROR | RANK ERROR | ||
2+/0.5 | 2+/0.5 | ||
∧ | ∧ | ||
</ | </source> | ||
A RANK ERROR may be caused when argument ranks are incompatible in some other way. In languages with [[high-rank set functions]] such as [[Dyalog APL]] and [[J]], the right argument rank must be at least the left argument rank minus one. Calling it with a matrix left argument and a scalar right argument, which has a rank two smaller, gives a RANK ERROR: | A RANK ERROR may be caused when argument ranks are incompatible in some other way. In languages with [[high-rank set functions]] such as [[Dyalog APL]] and [[J]], the right argument rank must be at least the left argument rank minus one. Calling it with a matrix left argument and a scalar right argument, which has a rank two smaller, gives a RANK ERROR: | ||
< | <source=apl> | ||
(⍳3 4) ⍳ ⊂1 3 | (⍳3 4) ⍳ ⊂1 3 | ||
RANK ERROR | RANK ERROR | ||
(⍳3 4)⍳⊂1 3 | (⍳3 4)⍳⊂1 3 | ||
∧ | ∧ | ||
</ | </source> | ||
{{Works in|[[Dyalog APL]]}} | {{Works in|[[Dyalog APL]]}} | ||
Revision as of 15:05, 17 October 2019
A RANK ERROR is an error message which indicates that an array had an incorrect rank for the way it was used. For example, in most APLs, Iota only accepts a vector or scalar, so giving it a higher-rank array results in a RANK ERROR: <source=apl>
⍳2 3⍴⍳6
RANK ERROR
⍳2 3⍴⍳6
∧
</source>
A RANK ERROR can be caused when arguments do not conform because they have differing ranks: <source=apl>
(2 3⍴2) + ⍳6
RANK ERROR: Mismatched left and right argument ranks
(2 3⍴2)+⍳6
∧
</source>
It may also be caused when an array's rank is too small for a function. Windowed Reduction is not defined on scalars: <source=apl>
2 +/ 0.5
RANK ERROR
2+/0.5
∧
</source>
A RANK ERROR may be caused when argument ranks are incompatible in some other way. In languages with high-rank set functions such as Dyalog APL and J, the right argument rank must be at least the left argument rank minus one. Calling it with a matrix left argument and a scalar right argument, which has a rank two smaller, gives a RANK ERROR: <source=apl>
(⍳3 4) ⍳ ⊂1 3
RANK ERROR
(⍳3 4)⍳⊂1 3
∧
</source>