In [1]:
1+3
Out[1]:
4
In [2]:
(2+3)*3
Out[2]:
15
Global Variables¶
In [3]:
integer :: i
In [4]:
integer :: j
In [5]:
i = 5
j = 6
In [6]:
i
Out[6]:
5
In [7]:
(i+j)*3
Out[7]:
33
Functions¶
You can declare a function and use it in expressions:
In [8]:
integer function fn(a, b)
integer, intent(in) :: a, b
fn = a + b
end function
In [9]:
fn(2, 3)
Out[9]:
5
In [10]:
fn(2, 3)*3
Out[10]:
15
You can redeclare a function and it will shadow the old fn function. Now fn(2, 3) returns a different value:
In [11]:
integer function fn(a, b)
integer, intent(in) :: a, b
fn = a - b
end function
fn(2, 3)
Out[11]:
-1
Control Flow, Printing¶
You can use loops, if statements or the print function.
In [12]:
integer :: i
do i = 1, 4
if (i == 3) cycle
print *, "variable i =", i
end do
variable i = 1 variable i = 2 variable i = 4
Plotting¶
You can do plotting using Matplotlib underneath:
In [13]:
integer :: i, tmp
do i = 1, 4
tmp = plot(1, i+1, 1)
end do
show()
Magic Commands¶
Compiler¶
In [14]:
integer :: i, j, n
n = 5
j = 0
Show Abstract Syntax Tree (AST) after parsing (based on syntax only, no semantics):
In [15]:
%%showast
do i = 1, n
j = j + i
end do
Parse AST: DoLoop(head=do_loop_head(var='i', start=Num(n='1'), end=Name(id='n'), increment=None), body=[Assignment(target=Name(id='j'), value=BinOp(left=Name(id='j'), op=Add(), right=Name(id='i')))])
Show LLVM code:
In [16]:
%%showllvm
do i = 1, n
j = j + i
end do
LLVM IR (optimized):
; ModuleID = '<string>'
source_filename = "<string>"
target triple = "unknown-unknown-unknown"
@i_0 = external local_unnamed_addr global i64
@j_0 = external local_unnamed_addr global i64
@n_0 = external local_unnamed_addr global i64
; Function Attrs: norecurse nounwind
define i64 @_run16() local_unnamed_addr #0 {
.entry:
store i64 0, i64* @i_0, align 4
%.73 = load i64, i64* @n_0, align 4
%.84 = icmp slt i64 %.73, 1
br i1 %.84, label %loop.end, label %loop.body.lr.ph
loop.body.lr.ph: ; preds = %.entry
%j_0.promoted = load i64, i64* @j_0, align 4
br label %loop.body
loop.body: ; preds = %loop.body.lr.ph, %loop.body
%.156 = phi i64 [ %j_0.promoted, %loop.body.lr.ph ], [ %.15, %loop.body ]
%.65 = phi i64 [ 1, %loop.body.lr.ph ], [ %.6, %loop.body ]
%.15 = add i64 %.156, %.65
%.6 = add i64 %.65, 1
%.8 = icmp sgt i64 %.6, %.73
br i1 %.8, label %loop.header.loop.end_crit_edge, label %loop.body
loop.header.loop.end_crit_edge: ; preds = %loop.body
store i64 %.65, i64* @i_0, align 4
store i64 %.15, i64* @j_0, align 4
br label %loop.end
loop.end: ; preds = %loop.header.loop.end_crit_edge, %.entry
ret i64 undef
}
attributes #0 = { norecurse nounwind }
Show assembly code:
In [17]:
%%showasm
do i = 1, n
j = j + i
end do
ASM:
.text
.file "<string>"
.globl _run17 # -- Begin function _run17
.p2align 4, 0x90
.type _run17,@function
_run17: # @_run17
# %bb.0: # %.entry
movabsq $i_0, %rax
movq $0, (%rax)
movabsq $n_0, %rcx
movq (%rcx), %rcx
testq %rcx, %rcx
jle .LBB0_4
# %bb.1: # %loop.body.lr.ph
movabsq $j_0, %rdx
movq (%rdx), %rsi
movl $1, %edi
.p2align 4, 0x90
.LBB0_2: # %loop.body
# =>This Inner Loop Header: Depth=1
addq %rdi, %rsi
incq %rdi
cmpq %rcx, %rdi
jle .LBB0_2
# %bb.3: # %loop.header.loop.end_crit_edge
decq %rdi
movq %rdi, (%rax)
movq %rsi, (%rdx)
.LBB0_4: # %loop.end
retq
.Lfunc_end0:
.size _run17, .Lfunc_end0-_run17
# -- End function
.section ".note.GNU-stack","",@progbits
Filesystem¶
Load and show an image file:
In [18]:
integer :: i, tmp
do i = 1, 4
tmp = plot(2, 1, i)
end do
savefig(1)
Saving to output1.png.
Out[18]:
0
In [19]:
%showimage output1.png
List the current directory:
In [20]:
%ls
total 84 -rw-r--r-- 1 certik certik 5774 Nov 16 14:21 Demo.ipynb -rw-r--r-- 1 certik certik 27981 Nov 29 12:49 output1.png -rw-r--r-- 1 certik certik 45214 Nov 29 12:49 show_output1.png