edp@jareth.enet.dec.com (Always mount a scratch monkey.) (04/13/90)
I reread the HP-48 manuals and made notes of things I had forgotten from the first reading and other things that occurred to me. Here they are: To plot sideways: Select parametric plotting, and, instead of plotting F(X), plot F(X)+i*X. The independent variable should be a list indicating your independent variable and the range. AUTO works. However, only single expressions can be plotted this way; equations of two expressions are rejected. Shift-right down-arrow does a VISIT with the appropriate environement (Equation Writer or Matrix Editor). RAND appears to use the same sequence that the 28 used: r' = r*m mod 10^15, where r is the seed or previous random number, which is retained to 15 digits, and m is a carefully chosen constant which is the same on the 48 and 28. The integrate operator does not accept a program as a parameter; to numerically integrate a program, it must be called via an algebraic. The "at" sign, @, which we have seen in programs posted to the net, delimits comments in command lines just as it does in objects being transferred. When editing, it may be convient to mark text to be deleted by placing @'s before and after the text instead of manually deleting it. In the VAR menu, shift-left and a menu key stores a new value in the variable. In addition to one-key alpha mode and alpha-lock, the alpha key can be held down while characters are typed. The Greek letter phi can be generated in alpha mode with O or o followed by "etc." (shift-right 9). EDIT, VISIT, VIEW (down arrow), and visit-VIEW (shift-right down arrow) can be used from within the Interactive Stack. After exiting the Interactive Stack, LAST STACK will restore the last stack. In the Plotter: Shift-left DRAW performs STEQ. Shift-right DRAW performs RCEQ. In the Graphics Environment: STO puts PICT on the stack as a graphics object. ENTER puts the current co-ordinates on the stack. Shift-left Z-box selects a new X range and autoscales the Y range. Z-box can be used with horizontal or vertical lines instead of a box, to zoom one axis while leaving the other unchanged. In the Equation Catalog: Shift-right EQ+ starts a new list. Shift-left EQ+ removes the last entry from the list. Strings can be entered with: C$ count text . . . or C$ $ text . . . (to end of command line) With temperature units, % operations perform conversions; * just works on the number. E.g., 3 degrees C 2 * gives 6 degrees C, but 3 degrees C 200 % gives 279.15 degrees C. In the Equation Writer: EDIT puts a subexpression in the command line for editing. STO and " put the algebraic on the stack as a graphics object or string. CLR clears the algebraic. +/- provides the EXPR operation while in the RULES menu. SSTv does not single-step into IFERR. The annunciator for warnings such as unacknowledged alarms or low battery stays on even when the calculator is off. Flag -58 turns off a number of messages, such as those associated with particular menus -- like the request to enter an equation and press NEW, the alarm notice in the TIME menu, et cetera. Flag -53 turns on parentheses that would not otherwise be displayed, such as in A*B*C. There are two flags for each of degrees/radians/gradians mode and rectangular/cylindrical/spherical modes. In each pair, one of the flags being clear causes the HP-48 to be in radians or rectangular mode, regardless of the setting of the other flag. Pressing RAD or POLAR changes the first flag without affecting the other one. Thus, RAD switches between DEG/RAD or GRAD/RAD and POLAR switches between rectangular/cylindrical or rectangular/spherical. If given a list, RCL will evaluate it and recall the result. I haven't dared to try a SYSEVAL, not even #10d -- does it work? -- edp (Eric Postpischil) "Always mount a scratch monkey." edp@jareth.enet.dec.com