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CAPA Functions LON-CAPA Differences (if any)
sin(x), cos(x), tan(x) &sin($x), &cos($x), &tan($x)  
asin(x), acos(x), atan(x), atan2(y,x) &asin($x), &acos($x), &atan($x), &atan2($y,$x)  
log(x), log10(x) &log($x), &log10($x)  
exp(x), pow(x,y), sqrt(x) &exp($x), &pow($x,$y), &sqrt($x)  
abs(x), sgn(x) &abs($x), &sgn($x)  
erf(x), erfc(x) &erf($x), &erfc($x)  
ceil(x), floor(x) &ceil($x), &floor($x)  
min(...), max(...) &min(...), &max(...)  
factorial(n) &factorial($n)  
N%M $N%$M  
sinh(x), cosh(x), tanh(x) &sinh($x), &cosh($x), &tanh($x)  
asinh(x), acosh(x), atanh(x) &asinh($x), &acosh($x), &atanh($x)  
/DIS($x,"nn") &format($x,'nn')  The difference is obvious.
Not in CAPA &prettyprint($x,'nn','optional target')  
Not in CAPA &dollarformat($x,'optional target')  
Not in CAPA &languages(@desired_languages)  
roundto(x,n) &roundto($x,$n)  
Not in CAPA &cas($s,$e)
Not in CAPA &implicit_multiplication($f)
web("a","b","c") or web(a,b,c) &web("a","b","c") or &web($a,$b,$c)  
html("a") or html(a) &html("a") or &html($a)  
jn(m,x) &j0($x), &j1($x), &jn($m,$x), &jv($y,$x) In CAPA, j0, j1 and jn are contained in one function, jn(m,x) where m takes the value of 0, 1 or 2. jv(y,x) is new to LON-CAPA.
yn(m,x) &y0($x), &y1($x), &yn($m,$x), &yv($y,$x) In CAPA, y0, y1 and yn are contained in one function, yn(m,x) where m takes the value of 0, 1 or 2. yv(y,x) is new to LON-CAPA.
random(l,u,d) &random($l,$u,$d) In CAPA, all the 3 arguments must be of the same type. However, now you can mix the type
choose(i,...) &choose($i,...)  
/MAP(seed;w,x,y,z;a,b,c,d)
Option 1 - &map($seed,[\$w,\$x,\$y,\$z],[$a,$b,$c,$d]) or
Option 2 - &map($seed,\@mappedArray,[$a,$b,$c,$d])
Option 3 - @mappedArray = &map($seed,[$a,$b,$c,$d])
Option 4 - ($w,$x,$y,$z) = &map($seed,\@a)
where $a='A'
$b='B'
$c='B'
$d='B'
$w, $x, $y, and $z are variables
In CAPA, the arguments are divided into three groups separated by a semicolon ;. In LON-CAPA, the separation is done by using [] brackets or using an array @a. Note the backslash (\) before the arguments in the second and third groups.
rmap(seed;a,b,c,d;w,x,y,z)
Option 1 - &rmap($seed,[\$w,\$x,\$y,\$z],[$a,$b,$c,$d]) or
Option 2 - &rmap($seed,\@rmappedArray,[$a,$b,$c,$d])
Option 3 - @rmapped_array = &rmap($seed,[$a,$b,$c,$d])
Option 4 - ($w,$x,$y,$z) = &rmap($seed,\@a)
where $a='A'
$b='B'
$c='B'
$d='B'
$w, $x, $y, and $z are variables
In CAPA, the arguments are divided into three groups separated by a semicolon ;. In LON-CAPA, the separation is done by using [] brackets (with create an unamed vector reference) or using an array @a. Note the backslash (\) before the arguments in the second and third groups (Which cause Perl to send to variable locations rather than the variable values, similar to a C pointer).
NOT IMPLEMENTED IN CAPA $a=&xmlparse($string) New to LON-CAPA
tex(a,b), tex("a","b") &tex($a,$b), &tex("a","b")  
var_in_tex(a) &var_in_tex($a)  
to_string(x), to_string(x,y) &to_string($x), &to_string($x,$y)  
capa_id(), class(), section(), set(), problem() &class(), &sec() capa_id(), set() and problem() are no longer used. Currently, they return a null value.
name(), student_number() &name(), &student_number()  
open_date(), due_date(), answer_date() &open_date(), &due_date(), &answer_date() Output format for time is changed slightly. If pass noon, it displays ..pm else it displays ..am. So 23:59 is displayed as 11:59 pm.
get_seed(), set_seed() Not implemented  
sub_string(a,b,c) &sub_string($a,$b,$c) perl  substr function. However, note the differences Perl intrinsic function, substr(string,b,c) starts counting from 0 (as opposed to 1). In the example to the left, substr($a,4,4) returns "ome ".
array[xx] @arrayname Array is intrinsic in perl. To access a specific element use $arrayname[$n] where $n is the $n+1 element since the array count starts from 0 In LON-CAPA, an array is defined by @arrayname. It is not necessary to specify the dimension of the array. 
array_moments(B,A) @B=&array_moments(@A) In CAPA, the moments are passed as an array in the first argument whereas in LON-CAPA, the array containing the moments are set equal to the function.
array_max(Name), array_min(Name) &min(@Name), &max(@Name) Combined with the min and max functions defined earlier.
init_array(Name) undef @name Use perl intrinsic undef function.
random_normal (return_array,item_cnt,seed,av,std_dev) @return_array=&random_normal ($item_cnt,$seed,$av,$std_dev) In CAPA the results are passed as the first argument whereas in LON-CAPA the results are set equal to the function.
random_beta (return_array,item_cnt,seed,aa,bb) @return_array=&random_beta ($item_cnt,$seed,$aa,$bb) NOTE: Both $aa and $bb MUST be greater than 1.0E-37. In CAPA the results are passed as the first argument whereas in LON-CAPA the results are set equal to the function.
random_gamma (return_array,item_cnt,seed,a,r) @return_array=&random_gamma ($item_cnt,$seed,$a,$r) NOTE: Both $a and $r MUST be positive. In CAPA the results are passed as the first argument whereas in LON-CAPA the results are set equal to the function.
random_exponential (return_array,item_cnt,seed,av) @return_array=&random_exponential ($item_cnt,$seed,$av) NOTE: $av MUST be non-negative. In CAPA the results are passed as the first argument whereas in LON-CAPA the results are set equal to the function.
random_poisson (return_array,item_cnt,seed,mu) @return_array=&random_poisson ($item_cnt,$seed,$mu) NOTE: $mu MUST be non-negative. In CAPA the results are passed as the first argument whereas in LON-CAPA the results are set equal to the function.
random_chi (return_array,item_cnt,seed,df) @return_array=&random_chi ($item_cnt,$seed,$df) NOTE: $df MUST be positive. In CAPA the results are passed as the first argument whereas in LON-CAPA the results are set equal to the function.
random_noncentral_chi (return_array,item_cnt,seed,df,nonc) @return_array=&random_noncentral_chi ($item_cnt,$seed,$df,$nonc) NOTE: $df MUST be at least 1 and $nonc MUST be non-negative. In CAPA the results are passed as the first argument whereas in LON-CAPA the results are set equal to the function.
NOT IMPLEMENTED IN CAPA @return_array=&random_f ($item_cnt,$seed,$dfn,$dfd) NOTE: Both $dfn and $dfd MUST be positive. New to LON-CAPA
NOT IMPLEMENTED IN CAPA @return_array=&random_noncentral_f ($item_cnt,$seed,$dfn,$dfd,$nonc) NOTE: $dfn must be at least 1, $dfd MUST be positive, and $nonc must be non-negative. New to LON-CAPA
NOT DOCUMENTED IN CAPA @return_array=&random_multivariate_normal ($item_cnt,$seed,\@mean,\@covar) NOTE: @mean should be of length p array of real numbers. @covar should be a length p array of references to length p arrays of real numbers (i.e. a p by p matrix. Note the backslash before the @mean and @covar arrays.
NOT IMPLEMENTED IN CAPA @return_array=&random_multinomial ($item_cnt,$seed,@p) NOTE: $item_cnt is rounded with int() and the result must be non-negative. The number of elements in @p must be at least 2. New to LON-CAPA
NOT IMPLEMENTED IN CAPA @return_array=&random_permutation ($seed,@array) New to LON-CAPA
NOT IMPLEMENTED IN CAPA @return_array=&random_uniform ($item_cnt,$seed,$low,$high) NOTE: $low must be less than or equal to $high. New to LON-CAPA
NOT IMPLEMENTED IN CAPA @return_array=&random_uniform_integer ($item_cnt,$seed,$low,$high) NOTE: $low and $high are both passed through int(). $low must be less than or equal to $high. New to LON-CAPA
NOT IMPLEMENTED IN CAPA @return_array=&random_binomial ($item_cnt,$seed,$nt,$p) NOTE: $nt is rounded using int() and the result must be non-negative. $p must be between 0 and 1 inclusive. New to LON-CAPA
NOT IMPLEMENTED IN CAPA @return_array=&random_negative_binomial ($item_cnt,$seed,$ne,$p) NOTE: $ne is rounded using int() and the result must be positive. $p must be between 0 and 1 exclusive. New to LON-CAPA