Obsidian Sigma

Obsidian is a great markdown-based note taking app. One of the key aspects of Obsidian is it's extensibility by using additional plugins.

Sigma is a plugin to enable using blocks within a note as calculation sheets.

Features

• Calculation expressions with proper operator precedence
• Automatic block level totals
• Support for multiple blocks in a single note
• Hierarchy and subtotals
• Variable assignment and evaluation
• Built in scientific functions
• Control over output number formatting
• Output in clean HTML tables for easy sharing
• Syntax coloring for expressions in output including dark theme
• Supported on desktop and mobile

Usages

• Financial planning,
• Expense tracking,
• Conversions,
• Miscllaneous calculations,
• And much more

Installation

• Install the Sigma plugin from the Obsidian community plugins list

Guide

• Use a code block (3 backquote characters) with a type sigma
• Write expressions on each line
• Each expression is evaluated
• All expressions in a block are totaled
• Once you exit the block (editing cursor moves out, or switch to read mode), the block is rendered as an HTML table with expression values and block totals

Exampels

Simple Calculation List

```sigma
12+3+5
13+9+44
2+3*4
2*3+4
2*(3+4)
```

Produces

1	12+3+5	20
2	13+9+44	66
3	2+3*4	14
4	2*3+4	10
5	2*(3+4)	14
		124

Word and Value

You can use a word as a prefix for an expression, separated by a colon character :

```sigma
test1: 12/3
test2: 98.7
```

Produces

1	test1: 12/3	4
2	test2: 98.7	98.7
		102.7

Words and Expressions

You can also use multiple words in a sentence as a prefix, however, you cannot embed numbers or other special characters within the sentence.

```sigma
multipe word sentence: 7+9
word1
word2: 2*9
```

Produces

1	multipe word sentence: 7+9	16
2	word1	0
3	word2: 2*9	18
		34

Negative Values

```sigma
-234
```

Produces

1	-234	-234

Hierarchy

Create hierarchies by using space indentation in code blocks. Sigma automatically adds all sub-items to the parent line

```sigma
Cat1
 Item1: 5
 Item2: 6
Cat2
 Item3: 7
 Item4: 8
```

Produces

1	Cat1	11
2	....Item1: 5	5
3	....Item2: 6	6
4	Cat2	15
5	....Item3: 7	7
6	....Item4: 8	8
		26

Assignment and variable

Variables can be evaluated later within the block

```sigma
someVar = 200;
someVar * 10;
```

Produces

1	someVar=200;	200
2	someVar*10;	2,000
		2,200

Built-in Functions

A number of scientific functions are built-in

```sigma
PI=3.141592276
sin(PI/4)
cos(PI/2)
tan(PI/4)
asin(1)
acos(0)
atan(0.7)
abs(2-4)/(2-4)
clamp(29,0,1)
```

Produces

1	PI=3.141592276	3.142
2	sin (PI/4)	0.707
3	cos (PI/2)	0
4	tan (PI/4)	1
5	asin (1)	1.571
6	acos (0)	1.571
7	atan (0.7)	0.611
8	abs (2-4)/(2-4)	-1
9	clamp (29,0,1)	1
		8.601

Line References

Even without explicitly naming a variable, each line is automatically referenceable by using Line and the line number

```sigma
Header1
 Value1: 1
 Value2: 2
Line1+6
```

Produces

1	Header1	3
2	.....Value1: 1	1
3	.....Value2: 2	2
4	Line1+6	9
		12

Complex Expressions

You can use parenthesis for compound expressions as you would expect in a programming language.

```sigma
abs(12-3)/(12-3)+9
```

Produces

1	abs (12-3)/(12-3)+9	10