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The Compleat User RPL Encyclopedia

(“Sigma Plus”)

 x y z ...  
Keyboard Access:
  HP-28: STAT
         RS-STAT LS-PREV
HP49/50: 97 MENU (a statistics submenu)
         91 MENU (a plotting submenu)
Sigma Plus command: Adds one or more data to the current statistics matrix (reserved variable ).

The very first execution of  (when does not exist, such as after ) stores whatever is in level 1 into (a single number or an array of numbers). That will determine the number of columns in the matrix:

All subsequent executions of  will expect the correct number of data on the stack (as determined in the previous paragraph), either as that many numbers on the stack, or as that many numbers in a vector on level 1, or as a matrix with that many columns. For example, if contains 2 columns, you can input the data pair (5, 7) either as [ 5 7 ] or as 5 on level 2 and 7 on level 1.  treats both input styles identically. To add more than one row of data at a time, put them in a matrix; e.g. [[ 5 7 ][ 6 9 ]]  adds both [ 5 7 ] and [ 6 9 ] as two new data pairs into .

If the input is numbers on multiple stack levels, and there are insufficient data on the stack,  will generate the “Too Few Arguments” error. If the input is a vector on level 1, and it has an incorrect number of elements, then  will generate a “Bad Argument Value” error. If the input is a matrix on level 1, and it has an incorrect number of columns, it will also generate a “Bad Argument Value” error.

after  always returns exactly one object: the newly added number or vector or matrix. If the input was on multiple stack levels, then they will all be returned in a vector by .

HP49/50 maximum integer input(s): Integer inputs on the HP49/50 are converted to reals by all statistics functions, including . Therefore, MAXI is the maximum integer input allowed by  even if flag -21 is clear.

Due to a harmless bug in the HP49/50,  does not store multiple stack level inputs of integer objects into correctly. For example, if has three columns, putting 1 2 3 on the stack in exact mode and executing  stores [1 2 3.] into (two integers and one real). Array inputs are stored correctly into : [1 2 3]     [1 2 3] (three integers). In both cases, [1. 2. 3.] is what gets added to .

See also:  

BYTES: 2.5