The origins of Indian classical music can be found from the oldest of scriptures, part of the Hindu tradition, the Vedas. The Samaveda, one of the four Vedas, describes music at length. The Samaveda was created out of Rigveda so that its hymns could be sung as Samagana; this style evolved into jatis and eventually into ragas. Indian classical music has its origins as a meditation tool for attaining self realization. All different forms of these melodies (ragas) are believed to affect various "chakras" (energy centers, or "moods") in the path of the Kundalini. However, there is little mention of these esoteric beliefs in Bharat's Natyashastra, the first treatise laying down the fundamental principles of drama, dance and music. Indian classical music has one of the most complex and complete musical systems ever developed. Like Western classical music, it divides the octave into 12 semitones of which the 7 basic notes are Sa Re Ga Ma Pa Dha Ni Sa. Indian classical music is monophonic in nature and based around a single melody line which is played over a fixed drone. The performance is based melodically on particular ragas and rhythmically on talas. Notation System Indian music is traditionally practice oriented and does not employ notations as the primary media of instruction/understanding/transmission. The rules of Indian music and compositions themselves are taught from a guru to a shishya, in person. Various Indian music schools followed notations and classifications (see Melakarta and thaat); however, the notation is regarded as a matter of taste and is not standardized. Thus there is no universal system of notation for the rest of the world to study Indian music. Scholars of Europe in the seventeenth and eighteenth century were enamoured by Indian music and with no facility to record the sound they explored for some existing system that might express sounds in the composition. There were pointers to an ancient notation system which scholars had also translated into Persian; still, the complexity of Indian classical music could not be expressed in writing. Though some western scholars did record compositions in the staff notation system, Indian musicians have used a system created by Bhatkhande in the 20th century. Though more accurate, this relies on Devanagari script rather than symbols and hence is cumbersome at times. A new notation system has been proposed which uses symbols and offers instantaneous comprehension like Staff notation system. It is with standardization of a notation system that hitherto unknown compositions would see the light of day. Hindustani music Players of the tabla, a type of drum, usually keep the rhythm in Hindustani music. Another common instrument is the stringed tanpura, which is played at a steady tone (a drone) throughout the performance of the raga. This task traditionally falls to a student of the soloist, a task which might seem monotonous but is, in fact, an honour and a rare opportunity for the student who gets it. Other instruments for accompaniment include the sarangi and the harmonium. The prime themes of Hindustani music are romantic love, nature, and devotionals. Yet, Indian classical music is independent of such themes. To sing a raga any poetic phrase appropriate for the raga may be chosen and the raga would not suffer. In Hindustani music, the performance usually begins with a slow elaboration of the raga, known as alap. This can range from very long (30-40 minutes) to very short (2-3 minutes) depending on the style and preference of the musician. Once the raga is established, the ornamentation around the mode begins to become rhythmical, gradually speeding up. This section is called the drut or jor. Finally, the percussionist joins in and the tala is introduced. There is a significant amount of Persian influence in Hindustani music, in terms of both the instruments and the style of presentation. Carnatic music Carnatic music tends to be significantly more structured than Hindustani music; examples of this are the logical classification of ragas into melakarthas, and the use of fixed compositions similar to Western classical music. Carnatic raga elaborations are generally much faster in tempo and shorter than their equivalents in Hindustani music. The opening piece is called a varnam, and is a warm-up for the musicians. A devotion and a request for a blessing follows, then a series of interchanges between ragams (unmetered melody) and thaalams (the ornamentation, equivalent to the jor). This is intermixed with hymns called krithis. This is followed by the pallavi or theme from the raga. Carnatic pieces can also have notated, lyrical poems that are reproduced as such, possibly with embellishments and treatments as per the performer's ideology; these basic pieces are called compositions and are popular among those who appreciate Carnatic (especially vocal) music. Compositions usually have amble flexibility in them so as to foster creativity: it is commonplace to have same composition sung in different ways by different performers. Carnatic music is similar to Hindustani music in that it is improvised (see musical improvisation). Primary themes include worship, descriptions of temples, philosophy, nayaka-nayaki themes and patriotic songs. Tyagaraja (1759-1847), Muthuswami Dikshitar (1776-1827) and Syama Sastri (1762-1827) are known as the Trinity of Carnatic music, while Purandara Dasa (1480-1564) is often called the father of Carnatic music.