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• Error messages: | ||
• Warning messages: |
This chapter provides detailed information about the meaning of some error messages or on how to recover from errors.
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One common cause for this error message is that square brackets operator
([ ]
) was used trying to access a list element that whose element
number was < 1
or > length(list)
.
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This normally means that a list, a set or something else that consists of more than one element was expected. One possible cause for this error message is a construct of the following type:
(%i1) l:[1,2,3]; (%o1) [1, 2, 3]
(%i2) append(l,4); append: argument must be a non-atomic expression; found 4 -- an error. To debug this try: debugmode(true);
The correct way to append variables or numbers to a list is to wrap them in a single-element list first:
(%i1) l:[1,2,3]; (%o1) [1, 2, 3]
(%i2) append(l,[4]); (%o2) [1, 2, 3, 4]
Categories: Error messages
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Maxima supports several assignment operators. When trying to define a function
:=
has to be used.
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This message notifies about a classical division by zero error.
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This might be caused by a command starting with a comma (,
) or by one comma
being directly followed by another one..
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Common reasons for this error appearing are a closing parenthesis without an opening one or a closing parenthesis directly preceded by a comma.
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This error message normally indicates that the file exists, but can not be read.
If the file is present and readable there is another possible for this error
message: Maxima can compile packages to native binary files in order to make them
run faster. If after compiling the file something in the system has changed in a
way that makes it incompatible with the binary the binary the file cannot be
loaded any more. Maxima normally puts binary files it creates from its own packages
in a folder named binary
within the folder whose name it is printed after
typing:
(%i1) maxima_userdir; (%o1) /home/gunter/.maxima
If this directory is missing maxima will recreate it again as soon as it has to compile a package.
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makelist
expects the second argument to be the name of the variable whose value is to
be stepped. This time instead of the name of a still-undefined variable maxima has found
something else, possibly a list or the name of a list.
Categories: Error messages
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The most probable cause for this error is that there was an attempt to either use a number or a variable whose numerical value is known as a loop counter.
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One possible reason for this error message to appear is a try to use append
in order
to add an equation to a list:
(%i1) l:[a=1,b=2,c=3]; (%o1) [a = 1, b = 2, c = 3]
(%i2) append(l,d=5); append: operators of arguments must all be the same. -- an error. To debug this try: debugmode(true);
In order to add an equation to a list it has to be wrapped in a single-element list first:
(%i1) l:[a=1,b=2,c=3]; (%o1) [a = 1, b = 2, c = 3]
(%i2) append(l,[d=5]); (%o2) [a = 1, b = 2, c = 3, d = 5]
Categories: Error messages
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Lisp typically handles several types of memory containing at least one stack and a heap that contains user objects. To avoid running out of memory several approaches might be useful:
--dynamic-space-size <n>
allows to tell
sbcl to reserve n
megabytes for the heap. It is to note, though,
that sbcl has to handle several distinct types of memory and therefore
might be able to only reserve about half of the available physical
memory. Also note that 32-bit processes might only be able to access
2GB of physical memory.
Categories: Error messages
Next: undefined variable during plotting, Previous: out of memory, Up: Error messages [Contents][Index]
part()
was used to access the n
th item in something that has less than
n
items.
Next: VTK is not installed, Previous: part fell off the end, Up: Error messages [Contents][Index]
A function could not be plotted since it still contained a variable maxima doesn’t know the value of.
In order to find out which variable this could be it is sometimes helpful to
temporarily replace the name of the drawing command (draw2d
, plot2d
or similar) by a random name (for example ddraw2d
) that doesn’t coincide
with the name of an existing function to make maxima print out what parameters
the drawing command sees.
(%i1) load("draw")$ (%i2) f(x):=sin(omega*t); (%o2) f(x) := sin(omega t) (%i3) draw2d( explicit( f(x), x,1,10 ) ); draw2d (explicit): non defined variable -- an error. To debug this try: debugmode(true); (%i4) ddraw2d( explicit( f(x), x,1,10 ) ); (%o4) ddraw2d(explicit(sin(omega t), x, 1, 10))
Categories: Error messages
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This might either mean that VTK is actually not installed - or cannot be found by maxima - or that maxima has no write access to the directory whose name is output if the following maxima command is entered:
(%i1) maxima_tempdir; (%o1) /tmp
Categories: Error messages
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• undefined variable during translation: | ||
• replaced x by y: |
Next: replaced x by y, Previous: Warning messages, Up: Warning messages [Contents][Index]
A function was compiled but the type of the variable x
was not known.
This means that the compiled command contains additional code that makes it
retain all the flexibility maxima provides in respect to this variable.
If x
isn’t meant as a variable name but just a named option to a
command prepending the named option by a single quote ('
) should
resolve this issue.
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Floating-point numbers provide a maximum number of digits that is typically high,
but still limited. Good examples that this limitation might be too low
even for harmless-looking examples include
Wilkinson’s Polynomial,
The Rump polynomial and the fact that an exact 1/10 cannot be expressed as a binary
floating-point number.
In places where the floating-point error might add up or hinder terms from
cancelling each other out maxima therefore by default replaces them with exact
fractions.
See also ratprint
, ratepsilon
, bftorat
, fpprintprec
and rationalize
.
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