all functions - e

earth_tilt
```
earth_tilt

Interpreted function, defined at i/kepler.i   line 429

```

edit_times
```
edit_times, file
or edit_times, file, keep_list
or edit_times, file, keep_list, new_times, new_ncycs

edits the records for FILE.  The KEEP_LIST is a 0-origin index list
of records to be kept, or nil to keep all records.  The NEW_TIMES
array is the list of new time values for the (kept) records, and
the NEW_NCYCS array is the list of new cycle number values for the
(kept) records.  Either NEW_TIMES, or NEW_NCYCS, or both, may be
nil to leave the corresponding values unchanged.  If non-nil,
NEW_TIMES and NEW_NCYCS must have the same length as KEEP_LIST,
or, if KEEP_LIST is nil, as the original number of records in
the file.  If KEEP_LIST, NEW_TIME, and NEW_NCYCS are all omitted
or nil, then edit_times removes records as necessary to ensure
that the remaining records have monotonically increasing times,
or, if no times are present, monotonically increasing ncycs.
(The latest record at any given time/ncyc is retained, and earlier
records are removed.)
In no case does edit_times change the FILE itself; only Yorick's
in-memory model of the file is altered.
Builtin function, documented at i0/std.i   line 3316

```

ell_am
```
ell_am(u)
or ell_am(u,m)

returns the "amplitude" (an angle in radians) for the Jacobi
elliptic functions at U, with parameter M.  That is,
phi = ell_am(u,m)
means that
u = integral[0 to phi]( dt / sqrt(1-m*sin(t)^2) )
Thus ell_am is the inverse of the incomplete elliptic function
of the first kind ell_f.  See help,elliptic for more.
Interpreted function, defined at i/elliptic.i   line 93

```

ell_e
```
ell_e(phi,m)

returns the incomplete elliptic integral of the second kind E(phi|M).
That is,
u = ell_e(phi,m)
means that
u = integral[0 to phi]( dt * sqrt(1-m*sin(t)^2) )
See help,elliptic for more.
Interpreted function, defined at i/elliptic.i   line 240

```

ell_f
```
ell_f(phi,m)

returns the incomplete elliptic integral of the first kind F(phi|M).
That is,
u = ell_f(phi,m)
means that
u = integral[0 to phi]( dt / sqrt(1-m*sin(t)^2) )
See help,elliptic for more.
Interpreted function, defined at i/elliptic.i   line 180

```

ellip2_e
```
ellip2_e(m)

returns the complete elliptic integral of the second kind E(M):
E(M) = integral[0 to pi/2]( dt * sqrt(1-M*sin(t)^2) )
accurate to 2e-8 for 0<=M<=1
Interpreted function, defined at i/elliptic.i   line 408

```

ellip2_k
```
ellip2_k(m)

returns the complete elliptic integral of the first kind K(M):
K(M) = integral[0 to pi/2]( dt / sqrt(1-M*sin(t)^2) )
accurate to 2e-8 for 0<=M<1
Interpreted function, defined at i/elliptic.i   line 391

```

ellip_e
```
ellip_e(m)

returns the complete elliptic integral of the second kind E(M):
E(M) = integral[0 to pi/2]( dt * sqrt(1-M*sin(t)^2) )
See help,elliptic for more.
Interpreted function, defined at i/elliptic.i   line 341

```

ellip_k
```
ellip_k(m)

returns the complete elliptic integral of the first kind K(M):
K(M) = integral[0 to pi/2]( dt / sqrt(1-M*sin(t)^2) )
See help,elliptic for more.
Interpreted function, defined at i/elliptic.i   line 303

```

eps
```
eps, name

writes the picture in the current graphics window to the Encapsulated
PostScript file NAME+".eps" (i.e.- the suffix .eps is added to NAME).
This function requires ghostscript.  Any hardcopy file associated with
the current window is first closed, but the default hardcopy file is
unaffected.  As a side effect, legends are turned off and color table
dumping is turned on for the current window.
The external variable EPSGS_CMD contains the command to start
ghostscript.
Interpreted function, defined at i0/graph.i   line 198

```

epsi
```
eps, name

writes the picture in the current graphics window to the Encapsulated
PostScript file NAME+".epsi" (i.e.- the suffix .epsi is added to NAME).
The eps function requires the ps2epsi utility which comes with the
project GNU Ghostscript program.  Any hardcopy file associated with
the current window is first closed, but the default hardcopy file is
unaffected.  As a side effect, legends are turned off and color table
dumping is turned on for the current window.
The external variable PS2EPSI_FORMAT contains the format for the
command to start the ps2epsi program.
Interpreted function, defined at i0/graph.i   line 178

```

eq_nocopy
```
eq_nocopy, y, x

is the same as
y= x
except that if x is an array, it is not copied, even if it is
not a temporary (i.e.- an expression).  Having multiple variables
reference the same data can be confusing, which is why the default
= operation copies the array.  The most important use of eq_nocopy
involves pointers or lists:
y= *py
z= _car(list)
always causes the data pointed to by py to be copied, while
eq_nocopy, y, *py
eq_nocopy, z, _car(list)
does not copy the data - often more nearly what you wanted.
Note that scalar int, long, and double variables are always copied,
so you cannot count on eq_nocopy setting up an "equivalence"
between variables.
Builtin function, documented at i0/std.i   line 326

```

erf
```
erf(x)

return erf(x), 2./sqrt(pi) * integral[0 to x](exp(-t^2)*dt)
Interpreted function, defined at i/dawson.i   line 50

```

erfc
```
erfc(x)

return erfc(x), 2./sqrt(pi) * integral[x to infinity](exp(-t^2)*dt)
Interpreted function, defined at i/dawson.i   line 72

```

erfc_nr
```
erfc_nr(x)

returns the complementary error function 1-erf with fractional
error less than 1.2e-7 everywhere.
Interpreted function, defined at i/gamma.i   line 84

```

error
```
exit, msg
error, msg

Exits the current interpreted *main* program, printing the MSG.
(MSG can be omitted to print a default.)
In the case of exit, the result is equivalent to an immediate
return from every function in the current calling chain.
In the case of error, the result is the same as if an error had
occurred in a compiled routine.
Builtin function, documented at i0/std.i   line 3439

```

evolve
```
evolve, time1
or evolve, time1, time0

Step the hydro calculation forward to TIME1,
starting with the initial conditions in the
RT, z, and v arrays at time TIME0 (default 0.0
if omitted).  The calculation also depends on
the constants M (mass/area/zone) and gammaM1
(gamma-1 for the gamma-law equation of state).
The pressure array p is updated in addition to
the primary state arrays RT, z, and v.
Boundary conditions are specified by setting
either a boundary pressure or a boundary
velocity at each end of the fluid column.
bc0_v   - Boundary velocity at z(0), or []
if z(0) has pressure BC.
bc0_p   - Boundary pressure beyond z(0).
bc0_time  - If bc0_v or bc0_p is an array,
bc0_time is an array of the same
length specifying the corresponding
times for time dependent BCs.
bc0_Z   - Acoustic impedance at z(0) if bc0_v
is nil (default is 0).
bcN_v, bcN_p, bcN_time, and bcN_Z have the same
meanings for the z(n_zones) boundary.
The worker routines OutputResults and
TakeStep must be supplied.
Interpreted function, defined at i/demo1.i   line 119

```

exit
```
exit

Builtin function, documented at i0/std.i   line 3439

```
SEE error

exp
```
exp(x)

returns the exponential function of its argument (inverse of log).
Builtin function, documented at i0/std.i   line 654

```

expm1
```
expm1(x)
or expm1(x, ex)

return exp(X)-1 accurate to machine precision (even for X<<1)
in the second form, returns exp(x) to EX
Interpreted function, defined at i0/std.i   line 672

```